Leonardo, often referred to as Leo, is one of the main protagonists of the 2012-2017 television series and the leader of the Ninja Turtles. He is also the oldest of the four brothers, who all share a home in the underground sewers of Manhattan, New York City. Leonardo is the adoptive son of Master Splinter and younger adoptive brother of Karai, who is his love interest. He belongs to a diverse family consisting of three other mutant turtles who are his biological younger ninjutsu brothers: Donatello, Michelangelo, and Raphael; and the ratlike Splinter, who serves as the Turtles' adoptive father and sensei. This version of Leonardo was originally voiced by Jason Biggs from the series premiere until Season 2 Episode 19. Leo‘s voice sounded exactly like his age. Leo’s voice actor got temporarily recasted by Dominic Catrambone for the final 7 episodes of Season 2 (nonetheless, his voice still sounds very similar) and finally replaced by Seth Green from Seasons 3 to 5. With Green as Leo's third voice actor, Leo's voice becomes more adult like. His change of voice is explained by the character having wounded his larynx (vocal cords) in the aftermath of the battle in the Season 2 finale.
Leo is an fern green colored anthropomorphic mutant turtle ninja warrior. His eyes have cobalt blue irises with black pupils, but like his brothers when they are shown fighting or being stealthy, they disappear, leaving his eyes white (similar to the 2003 incarnation). He wears a royal blue bandana mask (though he wears a black bandana in Broken Foot and Owari) where the tails length range between Donnie and Mikey's. Leo is the most skilled fighter, and he doesn't have much changes to his physical appearance like all his previous incarnations, except for the fact that his green skin is slightly darker than the others. His height ranges between Raph and Donnie's. His ninja gear includes brown knee pads and elbow pads, and beige rolled bandages wrapped around his wrists, ankles and fingers. However, unlike previous incarnations, Leo's hands have two fingers and a thumb and has 3 little toes (like his brothers).
Leo is an enthusiastic ninjutsu prodigy, who wears a royal blue headband, and fights with twin katana swords. He leads the various missions of the Turtles. Like previous incarnations, he is named after Leonardo da Vinci. Because of his persevering dedication towards ninjutsu, and his level-headed discipline, and partly because he asked for it, Splinter wisely chose Leo to be the leader of the Turtles. Leo is an enthusiastic ninjutsu prodigy, who wears a royal blue headband, and fights with (and wields) two twin katana swords called Niten Ryu. He leads the various missions of the Turtles. Like previous incarnations, he is named after Leonardo da Vinci.
Leo is the big brother of the turtle quartet. For the most part, he tries to be the mature and responsible older brother, but there are occasional times where he can be a very typical older brother, such as mocking Raph for reading The fantastic four food groups, beating up Mikey after using his comic book as toilet paper, or arguing with Donnie over Donnie‘s robo invention to take down the Kraang invasion. However he reassures his brothers especially Mikey when chaos emerges. Overall he’s very helpful.
Since the episode "The Deadly Venom", he is the only Ninja Turtle who is capable of using the spiritual, healing abilities of "the healing hands" technique to heal himself and others which enshrouds his body in a white aura by chanting the mantra and the right hand seals.
During an interview, Jason Biggs described Leo as "the glue who holds his brothers together and tries to keep them in line, saying things like 'Come on, guys! Focus and concentrate!' since he's a born leader who is very protective of his family."
Leo is a perfectionist. He wants to make his friends and family proud of him. When he makes a mistake he would go hard on himself. Although Leo tries to keep his brothers in line, he can be also very bossy and controlling at times which would trigger his brothers especially Raphael.
Being leader and later the sensei is a lot of responsibility, but it’s sometimes even harder when his three younger brothers talk back to him or team up to mock him.
Leo loves his favorite TV show called Space Heroes. He attempts to do impressions of Captain Ryan. He tries appear strong but it can also backfire as he makes rather cliché or ridiculous statements while trying to intimidate his enemies, such as introducing the team as the 'Mighty Mutants' or 'Turtles of Justice', while trying to appear heroic, or telling a scientist experimenting on a monkey that they'd had enough of him 'monkeying around'.
Even Leo can sometimes make rash decisions too, like doing crazy one man missions or his choice to spend time with Karai instead of helping his brothers. Although Donnie and especially Raphael are the ones who would really erupt when angry, Leo rarely erupts.
The 2012 series presented Leonardo as his typical self, retaining many of his developed character traits. His leadership qualities are ever-present (though several times already in the show’s short life, they’ve been the cause of much strife for the turtle), he maintains a strong dedication to his training, and he’s always fighting to protect his brothers’ lives. However, this time his achievements and struggles make sense, because the “teenage” part of the turtles is actually worked into the story.
The leader of the Turtles, Leonardo aspires to be a brave, decisive, perfect hero. Unfortunately, he's an inexperienced teen (for the moment at least) with three rowdy brothers. It's the gap between his aspiration and current situation that is the greatest source of frustration in Leo's life. He's the most driven of the four Turtles, training and studying relentlessly. He tends to be hard on himself, but his diligence does not go unnoticed; he is the favored student of Splinter, whose approval he very much craves.
Overall Leo is a helpful, adventurous, courageous, responsible, hardworking, protective, honorable, respectful, and enthusiastic ninjutsu prodigy with a "can-do" attitude. He is the most serious, disciplined, cool-headed mature and focused of the team.
Fifteen years before Rise of the Turtles, Part 1, Leonardo and his brothers were once ordinary turtles; when they were infants the benevolent Hamato Yoshi purchased the four as pets. When their soon-to-be father walked passed a strange man, he felt something odd about him and followed. Unfortunately Yoshi gave away his position when he accidentally stepped on a brown rat's tail. The Kraang found him and attempted to kill him, but Yoshi fought back hard.. During the scuffle, the aliens dropped a container of mutagen, Yoshi, having to have stepped on that rat, thus mutated into a humanoid brown rat by the name of "Splinter", While Leo and his brothers, after having been in contact with Yoshi and the clerk of the pet store where they were bought, mutated into humanoid turtles. Yoshi raised the turtles as his own children and to train them in Ninjutsu.
Splinter knew they would never be accepted in society and with the Kraang hot on his trail, the five of them lived in an abandoned water tower and a warehouse avoiding detection. During all of these trials, Splinter and the Turtles bonded and after he noticed the baby turtles trying to copy his Ninjitsu training, Splinter decided that there was an opportunity to turn this new life he was thrust into to his advantage, Taking one of his favorite books about the Renaissance art named them after the Artists he admired the most.
After last fight against the Kraang in the sewers in Splinter overheard the Kraang talking about how it became impossible for them to track Splinter and the Turtles there, Splinter decided to remain there. Thus making it that Splinter had found the safe environment where he could raise his adopted sons. . Knowing the world would be dangerous and there would be a time where they want to explore the outside world, Splinter started to train the boys in the art of Ninjitsu.
Skills, Powers and Abilities
Leonardo is the most stern, serious, focused, disciplined, responsible and among his brothers, being able to take on much larger opponents quicker and more easily in addition to coping with hectic stress.
- Leadership: Leonardo's bravery, determination, and willpower make him a great leader. In the beginning, his only flaws as a leader were due to his lack of experience (mostly due to his teenager status). His immaturity also caused him to occasionally make impulsive decisions that might make the situation worse, as well as his brothers sometimes disobeying his orders, and a desire to be a hero that results in him making rather poor taunts in battle. His most significant fear is to let the team down and fail as their leader. However, as he and his brothers continued to fight against the Shredder and his forces, Leonardo becomes more focused and disciplined as a leader, even becoming willing to sacrifice his own life for the sake of others. He's also able to make difficult choices whenever the situation came down to it. A note to make is that Splinter truly believed that Leo was destined to become the leader of his brothers ever since he was a small boy.
- Kenjutsu: Leonardo is a highly skilled martial artist and master swordsman. Leonardo was trained by Splinter in Japanese sword fighting. As his signature weapons are his twin katana, he is highly skilled in the sword fighting style of the Niten Ichi-ryū,(二天一, "two heavens as one"), making him an excellent swordsman. He makes use of his katana for skilled offense and defense, allowing him to slice through the metal of the Kraangs' robot bodies, as well as the Foot-Bots (stabbing and dismembering them), deflect shuriken and lasers. His skills with his swords enable him to fight against powerful and skilled members of the Foot Clan including Tiger Claw, Karai (until she discovered the truth about her origin), and even The Shredder, able to push him back even slightly during their fights.
- Ninjutsu Mastery: Through years of vast amount of training, Leonardo is a master of ninjutsu.
- Tantōjutsu: Aside from his swordsmanship Leonardo is also skilled with a tantō. Whenever he finds himself without his either of his katana, Leo can take the tantō from the handle of one of them and use it for self-defense.
- Kyūjutsu: Leonardo also possesses aptitude in archery and uses a yumi and arrows to fight long-ranged.
- Shurikenjutsu: Leonardo can throw shuriken with remarkable accuracy.
- Master Weaponry: In The Pulverizer Returns!, Leonardo learned to adapt his surroundings and shown to use other non-weapons, such as a metal pipe to fight the Foot Clan.
- Teaching: Leonardo is a highly skilled in teaching others. In Wanted: Bebop & Rocksteady, he shown his 1987 counterpart and other 1987 ninja turtles the accurate and extensive way of fighting in both armed and unarmed combat during their basic training.
- Master Combatant: Leonardo is known as to be the best combat fighter in the team of Ninja Turtles. His prowess skill shown to be able to defeat an army of Foot-Bot as well as Shredder's best henchmen during the Invasion on his own. Leonardo managed to ultimately defeated the Super Shredder when the mutation was stable with him cutting his head off at the top of Shredder's house.
- Enhanced Strength: Leonardo is the second physical strongest of the turtles, as he was shown to be beaten by Raphael during their early scuffles and training sessions, but he had also beaten him at times too. However, he is stronger than Donnie and Mikey (as seen in Mousers Attack! where he and Raph consider themselves as the two strongest fighters). Leo possess enhanced strength that gives him an advantage in a fight, such as overpowering the Foot Clan humans with no difficulty in The Pulverizer Returns!. Not only is he able to deliver powerful blows with his physical attacks, but he is able to throw heavy objects (including people) over his head. He is also able to knock back and hold his own against larger and/or physically stronger opponents.
- Enhanced Speed and Reflexes: Leonardo is able to move at great speed, able to free run on rooftops without losing momentum. He also possesses great reaction speed, allowing him to dodge projectiles such as lasers the Kraang's blasters, and enemy attacks. He can also spin swing twin katana at incredible speed as well. Despite being a turtle, he is not slow. He can run fast enough to avoid laser fire from a Kraang weapon. He can also move things at enhanced speeds too, like twirling his katana blades. In Rise of the Turtles, Leo was shown to deflect the laser fire from a Kraang weapon with both of his katanas.
- Enhanced Agility: Leonardo has the ability to coordinate his bodily to levels that are beyond the finest human athletes. In New Friend, Old Enemy, he along with his brothers was shown to acrobatic flips from one building to another building at further distance. In I Think His Name is Baxter Stockman, Leo was agile enough to quickly leap up to a building while using each step of his foot.
- Master of Stealth: Being taught by Splinter, Leonardo, as well as his brothers, are able to be one with darkness and hide and move within the shadows without being noticed. Like his brothers, he is stealthy, can hide in the shadows, sneak around without being detected, and use hand to hand combat like a real ninja.
- Retractable limbs into Shell: Though rarely (if ever) depicted, he has retractable limbs and the normal ability of a turtle to retract his head and limbs into the safety of his shell.
- Enhanced Healing: In the events of The Deadly Venom, Splinter taught Leonardo a unique ancient secret art and healing technique known as the Healing Hand. With the technique, Leonardo is able to heal himself and others, and even remove Karai's venom from his body despite there being no known cure for it. According to Splinter, he shows great gifts as a healer, and that being at the edge of his life had given him "a power that few martial artists can tap." His healing factor seem to work while in water, where he woke up after being ambushed by the Foot Clan during the Kraang Invasion 3 months later, but the fight left him injured.
- Intelligence: He has a good line of defense, and is the best at planning strategies. In most episodes, he's highly capable of improvising the objects around him to his advantage.
- Improvising: In most episodes, he's highly capable of improvising the objects around him to his advantage. Which is essential to his leadership abilities especially when he's on constant pressure.
- Enhanced Stamina and Endurance: Leo possesses a high stamina and much more than his brothers and Olympic-level athletes. During The Invasion, he was able to handle and stay much alive while fighting the long Foot-Bot challenge and defeat all of Shredder's henchmen, but all that work worn him out giving Shredder the chance to finish him off. Leonardo is very resilient to great amount of injury. In Metalhead (episode), Leo was able to withstand the impact after falling from several stories of a building without any sign of discomfort and injury.
His signature weapons of choice here are purely dual twin katana (刀) swords, which he uses and fights in the Niten Ryu (also known as Niten Ichi-ryu "The strategy of two heavens as one") style of kenjutsu, making him a skilled and excellent swordsman (although referred to as katanas, Leonardo's swords are actually much more closely modeled around the "Ninjatō" (忍者刀 ninjatō), (also known as ninjaken (忍者剣) or shinobigatana (忍刀)), a fictional sword similar to the katana, depicted as being a ninja's version of the weapon. It is usually straight-bladed, has a square guard, and is shorter than katana. . The handles have the same dark red and gold color that Raph's sai and Mikey's nunchucks have. Unique from his brother's weapons (Bo-Staff, Sai, and Nun-Chucks) Leo's weapons are the only ones specifically designed to deliver killing blows, though Leo is much too honorable to want to do so. You know what they say,"two swords are better than one."
In this incarnation, he's still very much learning to be a master swordsman (especially when compared to the 4Kids Leonardo). However, he's showing encouraging signs of it.
It's is implied that Leonardo has multiple identical katana swords stashed at the lair, such as when he is shown returning to the Turtles' underground lair after a fight with only one katana (having lost the other katana during the brawl) but is later shown with two katana swords sheathed on his scabbards.
Typically, Leonardo wields a pair of katana; one Daitō (大刀), a catchall word for the larger sword in a daishō pair (the word itself refers to the length of the blade, which was usually 70-90 cm) and one Shōtō (小刀) or Kodachi (小太刀), a catchall word for the shorter sword in a daishō pair. ("Kodachi" can also be used to refer to a blade that was similar to a wakizashi, but designed to be used by itself rather than in combination with a katana.), which, like his brothers with their chosen weapons, he is highly skilled with.
In Pulverizer Returns, Splinter says that the boys are getting too reliant on their own weapons, which makes them swap. After this process, Leonardo is left with Donatello's bō staff. During a fight, the turtles become uncooperative with their new weapons and swap back. When Splinter finds out, he takes away all weapons, stating that anything can be useful in battle. When Leonardo and his brothers are trying to save Timothy, Leonardo uses a metal pipe, which he holds and fights with it in a style similar to his katanas. In Turtle Temper and The Gauntlet, he also used a Yumi bow and like the rest of his brothers wields shuriken.
The handles of his katana blades also double as holsters for smaller tanto knives, as seen in The Manhattan Project, Part 2 and the season 2 finale, The Invasion, Parts 1 and 2, when he was battling the Shredder's minions.
When fighting a mind-controlled Raph in Clash of Mighty Mutantanimals, he shown a proficient use with a spear.
During his time in space during the first half of Season 4, Leonardo used a pair of space katana blades and a laser blaster created by Fugitoid. In the Season 4 finale and the Season 3 episode "Vision Quest", he was shown to fight with a bow and arrows.
Throughout much of the fifth and final season, Leonardo used a new, different type of swords (O-katanas) as his main weapon (the same ones he used in Season 4 episodes Broken Foot and Owari) in which the blades are longer and narrower with curved edges (the handles of his new O-katanas are black, as apposed to the typical red-and-gold colored handles), after shattering his original sword in an attempt to strike the evil demodragon Kavaxas. In the 4-episode Monsters vs. Mutants story arc Leo is given a wooden stake-shooting gun by Renet.
- Splinter- Leonardo's surrogate father and sensei. Like all of his incarnations, Leonardo is the most loyal and the closest towards his sensei, as he always takes Splinter's advice seriously. He spends a lot with his sensei, asking questions and having private discussions. Leonardo was devastated at Splinter's death at the hands of Shredder in Annihilation: Earth!, Part 2. Throughout season 4, he communicated with holograms of his master and when the turtles returned to earth he was quick to warn Splinter of Shredder's betrayal which saved him. Reunited with his master, Leonardo was eager to catch up on his adventures in space with him after he was curious. However, when Splinter died permanently, Leonardo stayed at his grave the longest out of everyone once more sad at his loss but he knows that his father is still there in his heart.
- Karai - It is also shown that during their first encounter, amid their sword duels and fencing challenges, Leonardo developed secret romantic feelings for Karai from the moment they first met. Leo didn‘t know at the time that she is Splinter’s true first born child and only daughter who was kidnapped by the Shredder after her mother's death. Shredder wanted revenge so he uses Karai to destroy her birth family. Leo eagerly wants to be able to trust Karai, although she had disrespect for him, his family and friends because Shredder wants them dead and Karai had to do what Shredder said. He still finds a special bond with Karai, though knowing that she is Master Splinter’s lost daughter gives him more reason to fight to save her from Shredder’s control. Raphael disapproves of Leonardo's association with Karai, considering Karai a threat to their survival and Leonardo a liability for so frequently giving Karai the benefit of the doubt. Although Karai told Leo that Shredder is her father in the past, Splinter later confessed to Leo that Karai was actually Hamato Miwa, his daughter and Leo was the first to know. In one episode, Leo made it very clear if Karai dared to harm his family, he would stop her himself. Despite that, Leo never gave up on the young girl. He knew all along that Karai is in a difficult situation especially when is caught in the middle between Splinter and Shredder. Leo decided to get Karai out of Shredder’s control. He gave her the truth about her life especially the part when Shredder was being dishonest to get his way. At first Karai was not having any of it, but when she began to reflect, she finally decided to seek the truth for herself. After genuinely realizing the truth wasn‘t a trap, at last a breakthrough. Leo finally got Karai to come around. She became a lot closer to Leonardo. When Karai was captured again, Leonardo struggled without success to save her from falling into a vat of mutagen, which turned her into a snake mutant. Soon many dilemmas came into play in Season 3. By Season 4, Leo and Karai bonded a lot more than they ever did. When Leo killed the Shredder, Karai was grateful that Leo ended the Shredder something she couldn't do when she tried. Relationship-wise, Leonardo's attachment to Karai is two-fold: he is in love with her and has also come to consider her part of his family since she is the biological daughter of his father Hamato Yoshi.
- Raphael - Leonardo has a love-hate relationship with his second younger brother Raphael. He and Raphael argue the most amongst all of the turtles, especially concerning who should lead the pack. However, they share deep respect for one another. In Showdown, Part 1, it is shown that Raphael is very protective about Leonardo and cares deeply for his brother, just like Leonardo does for him. It is seen that the two trust each other more than the others as seen how they often discuss things privately away from the others such as Leonardo's issue with Karai. As the series progresses, Leo's rivlary with Raph softens, and when crucial moments come, the two save each other. During the end of Season 2 and early Season 3, Raph became more sympathetic towards Leo. By Season 5 Raph began to respect Leo more than he ever did because Leo has all the authority as a sensei to stop Raph from talking back to him.
Donatello - Leonardo's third youngest brother. Leo and Donnie are very close but sometimes they argue. Occasionally, Leo would question Donnie’s inventions which drives Donnie mad. When Donnie is working hard on the tech and Leo (and Raph) to tell him to work faster or try harder, Donnie would snap or lash out at him. Like Raph, Donnie would also challenge Leo’s authority and leadership. In the Season 2 finale, Leo and Donnie got into a slanging match over how to stop the Kraang invasion. while Donnie wanted to hold their ground, staying at the city and fight them off with the Turtle Mech, despite the fact that his invention was still under construction while Leo recomended that they pack up their valuables, abandon the sewers and leave the city. During the 3rd episode of Season 5 (Heart of Evil), Donnie's resentment against Don Visiozo endangered the Turtles' mission, leading to argument between the two brothers, who eventually made up at the end of the episode. Overall the two work well together. Whenever the two team up together, Mikey calls them ”the team brainiac“.
- Michelangelo - Leonardo's youngest brother. Leo is usually patient with Mikey but sometimes he can get frustrated with him. One time Mikey used his favorite comic book as toilet paper to get his attention and Leo was not happy about it and he got very physical with him. Otherwise, Leo is very helpful with Mikey. Whenever Leo makes a plan, he sometimes makes sure that Mikey is really listening and focusing. Leo is also very protective of Mikey, saving him from danger several times. They also work quite well together to save their brothers and human friends from Bebop and Rocksteady and to acquire a worm to cure Karai. Overall, the relationship between the oldest brother and the youngest brother is a very close bond.
- April O'Neil - Leonardo's first human friend. He saves April from the Kraang as seen in the first two episodes of the first season: Rise of the Turtles, Part 1 and Rise of the Turtles, Part 2. They are very good friends, and April was the one Leonardo sought out when searching for advice regarding his crush on Karai. Leonardo's friendship with April is somewhat similar to a brother/sister relationship, when one looks after the other, like when April called for Leonardo to save her from the Creep in Within the Woods, and when Leonardo gives her hope in seeing her mother again in Buried Secrets.
- Casey Jones - Leonardo's second human friend. He met Casey in the eighth episode of the second season: The Good, The Bad and Casey Jones. Leonardo often calls Casey for help and Casey would come to help out. While they barely interact, they remain good friends.
- Leatherhead - Though they are allies, Leonardo and Leatherhead are almost never seen interacting, apart from fighting the Kraang. Leatherhead seems to interact more with Donatello and Michelangelo.
- Slash: Leonardo and Slash are allies, but not good friends. Leo views Slash with suspicion and distrust since the events of Slash and Destroy, while Slash is easily antagonized by Leo and prefers not to work with him. Nevertheless, Slash considers Leo a role model in his own efforts to be a good leader to the Mighty Mutanimals, and finally admits this to Leo at the end of Battle for New York, Part 2 and Leo apologize to Slash for distrusting him in the first place and the two make amends afterwards.
- Timothy - Leonardo never interacted with Timothy (the Pulverizer) as much, but he always gets annoyed whenever the Pulverizer tries taking too many risks that could get him injured or even killed (The Pulverizer Returns!).
- Shredder - Leonardo's arch-nemesis. Out of all the turtles, Leonardo seems to be the one who has the most interactions and the most hatred towards him. He is most aware of Shredder's moves among all his brothers, but still fails to fight him well. Shredder is much more experienced at ninjutsu and has more skills that Leonardo almost always fails to recognize, but Shredder only fails to kill Leonardo and his brothers, as they keep on escaping to the Sewers of Manhattan, NYC. Leonardo was the one who ended Shredder’s life by putting an fatal blow on the villain.
- The Kraang - Leonardo's targeted enemy. Relationship is unknown.
- Baxter Stockman - One of Leonardo's archenemies. Leonardo tends to forget Baxter's name (examples: "Dexter Backsman", "Daxter Boxman", "Blister Speckboy", etc.).
- Fishface - One of Leonardo's enemies. Relationship is unknown.
- Rahzar- One of Leonardo's enemies. It is a thought that he is worried about Michelangelo battling him. When they find out that Michelangelo is in danger, he says that they have to save him. He was the one who cut the ropes off Michelangelo and then pats him on the head.
- Leonardo is named for the famous Renaissance master, Leonardo da Vinci.
- Leonardo's name is Italian, meaning "Strong as the Lion/Lion-Bold".
- His name in Katakana is レオナルド (Reonarudo).
- Niten Ryu ("Two Heavens Style"), is described as Leonardo's weapons, but it is in fact the name of a fighting style for Japanese swords, and not a weapon. A two-sword set-up is properly known as a daisho, (大小). Niten Ryu, instead, is short for Niten-ichi Ryu, (二天一流), a two-sword style developed by legendary samurai Miyamoto Musashi.
- Leonardo's swords, whilst being referred to as "Katana", are actually "Ninjatō" (忍者刀 ninjatō), (also known as ninjaken (忍者剣) or shinobigatana (忍刀).
- The existence of the ninjaken has been up for debate for many years.
- Leonardo's swords, whilst being referred to as "Katana", are actually "Ninjatō" (忍者刀 ninjatō), (also known as ninjaken (忍者剣) or shinobigatana (忍刀).
- According to the Concept Art of Leonardo's Katana, "Niten Ryu", one sword is longer than the other, and a Tanto blade is concealed within the hilt of the "Daito" (Long Sword), and a "Kogatana" (Mini Tanto) is concealed within the Saya's (Scabbard's) binding wrappings, all as secondary, auxiliary weapons to his Katanas.
- His mastery of Ninjutsu includes: Seishin teki Kyoyo, Taijustu, Qigong, Kenjustu, Shurikenjustu, Kayakujustu, Shinobi-iri, Sui-ren, Boryaku, Kyuudou, and Intonjutsu.
- Leonardo seems to be the most educated (out of the four brothers) about Japanese culture and etiquette:
- He understands Japanese when spoken to and is able to speak in this language to some extent.
- He knows, at least basics, of Japanese etiquette (i.e. he bows to Master Splinter) as first seen in "Rise of the Turtles, Part 1".
- His caller ID on April's phone is "ichiban turtle", which means "number one turtle".
- He is the oldest of his brothers; the remaining age order is Raphael, Donatello and Michelangelo.
- Of all the turtles, he's the most mature:
- He was made leader by Splinter's choice.
- He sometimes acts like a parent to Michelangelo.
- Unlike his brothers, Leonardo always takes Splinter's advice seriously.
- Leonardo has a tanto blade hidden under his wrist wraps, as seen in "TCRI".
- This version of Leonardo places his swords on his back in the same fashion as his original Mirage counterpart, side by side instead of crossed.
- When Leonardo's voice actor was changed between seasons two and three, it was explained in-show as being the result of damage to his larynx during his battle with the Foot Clan in "The Invasion, Part 2".
- Since then, he was hence forth and for the duration of the series voiced by Seth Green.
- His favorite show is Space Heroes.
- He is right-handed.
- According to his concept art, Leo loves watching Saturday morning cartoons.
- Leo is first seen without his mask in "Within the Woods" when all his gear was removed to help him heal better after he was beaten down hard by the Shredder.
- He is also the third turtle to be seen maskless.
- Leo is also the first turtle to be seen without his gear.