Leonardo in the 2003 TV series, voiced by Michael Sinterniklaas, is the leader of the group. He is the most mature and responsible of the four brothers, and takes honor and responsibility as his priority.
Physical Appearance
Leonardo appears to be a normal, healthy teenage mutant turtle. He is muscular and stocky like his brothers. His skin tone is forest green and wears a blue ninja mask. For the fourth and fifth seasons, a small part of Leo's shell was cracked.
Personality
Leonardo is the leader with honor, sensitivity, calm, and reassurance. He’s most "spiritual" of the four. He is kind of a grown-up, psychologically because of all of his seriousness.
He has a very close bond with Splinter, and has a strong sense of honor and ethics, along with being a dedicated follower of the Bushido code. Episodes that deal with the Shredder and honor usually also focus on Leonardo, and he is often the Turtle who "saves the day" (in fact, Leonardo is the turtle who decapitates t he Shredder early on in the series—of course, before they are aware that Shredder is in fact an evil Utrom by the name of Ch'rell who doesn't have a neck, let alone a distinct head).
Raphael and Leonardo occasionally argue, although the two are shown to be very close. Despite this, all three of his brothers view him as a pillar of strength and are at a loss when he is injured or absent. One of Leonardo's most prominent qualities is his determination to believe the best in people, even potential enemies (i.e., Karai, Traximus and Quarry).
Leo may be the most mature but don’t be fooled. When Leonardo loses his temper, he would have emotional outbursts just like Raphael would if he was upset. Sometimes his explosive outbursts can be more violent and raging than Raphael’s. The first half of the fourth season shows a more traumatized, dark Leonardo, due to his feelings of failure, as did a short period in season one after the Shredder returns, in which he became depressed and angry. It wasn’t until he accidentally injured Splinter and subsequently received training from the Ancient One that his personality returned to his normal calm, happy, and reassuring self.
Biography
Childhood
Young Leonardo
Leonardo was a pet turtle bought by a young boy along with three others, Donatello, Raphael and Michelangelo. The boy was waiting at the crosswalk when a teenager noticed a blind old man crossing the street while a truck sped toward him. The teenager bumped into the boy with the turtles, causing him to drop the jar in which he held them. The turtles fell into the sewer. Meanwhile, the teenager had successfully saved the old man's life. While the truck veered away from the scene, the doors flew open and a canister fell right into the sewer with the turtles, covering them with an odd substance. A rat by the name of Splinter was passing by and picked up the turtles, touched the odd chemical as well, when one of the turtles shook it all over him. When Splinter woke up the next morning some point later, he found he and the turtles had grown taller, and slightly more intelligent.
Splinter thought it wise to train them in ninjutsu, just as his Master Yoshi had unknowingly done for him. Leonardo and his brothers were taken by Splinter to Japan when they were children to bury Hamato Yoshi's ashes with Tang Shen's remains, and alerted the Ancient One of his and Yoshi's condition. The turtles constantly noticed an odd demon visible to them, but invisible to the Ancient One and Splinter. Finally, when the Ancient One went to consult with the Ninja Tribunal, Splinter noticed an odd smell in the air, believing it to belong to the demon the turtles continued to see, and they secretly followed the Ancient One. The two ninja masters finally were attacked by the demon, but Don managed to throw a stone at the amulet, causing it to shatter and reveal the demon. The Ancient One and Splinter quickly killed the demon. The Ninja Tribunal applauded the turtles' efforts, though eradicated all memories of the trip. The Ancient One gave the turtles bandanas, Leonardo's being blue. The Tribunal used their connection with nature to wrinkle space and open a portal to the turtles' current lair.
Later, Leonardo found Donatello pursuing a remote-control car that had gotten caught in the flow of the sewer water. Donatello's life was endangered by large amounts of sewer garbage, but Leo managed to free his brother.
At some point, Splinter had discovered Leo was afraid of heights and trained him for weeks to conquer it. When it proved fruitless, Splinter faked a fall, which succeeded in forcing Leo to conquer his fear by focusing on saving his father.
Even as a child, it was shown that Leonardo was extremely focused on his training, able to ignore Michelangelo's antics until the latter tried to fight him which resulted in the latter's foil.
Seasons 1-4
Leonardo was introduced in the first season where he and his brothers are fighting Purple dragons for the first time. In The Shredder Strikes ,Part 1 Leonardo is almost tricked by the Shredder when the latter offers him to join the Foot Clan. After consulting Master Splinter, he then rejects the offer. In The Shredder Strikes, Part 2, The Shredder battles them, and plots to destroy Leonardo but is defeated. In The Shredder Strikes Back, Part 1, and The Shredder Strikes Back, Part 2, Leonardo goes out for a morning run where he is ambushed and defeated by the Foot Ninja, Hun, and the Elite Foot Ninja and finally the Shredder. He lands in April's apartment where the others help to evacuate him out. After the Shredder burns down April's apartment the gang retreats to a farm house. During this time Leonardo is in a coma but his driving spirit frees him. In The Monster Hunter, while Donatello, Michelangelo, and Casey Jones are helping a creature escape a scientist. Raphael helps Leonardo, by helping to forge him new katana swords.The gang eventually returns to New York in the Return to New York trilogy and at the end Leonardo uses the Sword of Tengu to defeat the Shredder. After that Master Splinter goes missing, and the Turtles infiltrate the T.C.R.I Building to find him but are found out by the Utrom and are teleported into outer space. After arriving in space Leo and his brothers help Professor Honeycutt in a series of mayhem against the Federations and Triceratons. The are blasted back to earth were the battle the Shredder and his army in the T.C.R.I building. Leonardo becomes angry that with the Shredder's defeat, the Foot, Mob, and Purple Dragons have engaged in a war for control of New York. Raphael tells Leo not to get involved in the war but Leo ignores him. Leo also meets Karai in this arc. Leo also battles the Ultimate Ninja, and wins. In the Season 2 finale arc the Turtles get sent to the Battle Nexus tournament. Leo befriends Usagi a samurai rabbit who also honorable and shares Leo's interest in swords and Bushido. In Season 3 multiple things happen: the Triceratons invade Earth, the Fugitoid returns, the Turtles meet Agent Bishop, and meet Renet in which they travel through time with the Time Scepter. Ultimate Drako returns and plots to scatter the turtles across time and space. Leo gets sent to the world of his best friend Usagi. In the Season 3 finale, Exodus,Part 1, and Exodus,Part 2, The turtles confront Shredder for the final time. The Shredder is planning on leaving Earth to control galaxies. But is stooped by the Utroms and is sent to permanent exile. This event causes a dramatic change in Leonardo. For the first half of the fourth season, Leonardo develops Post Tramatic Stress Disorder (PTSD) when he becomes mentally damaged because of the turtles final fight with the Shredder. He believes he wasn't good enough a leader to save his family without the Utroms rescuing them. This goes on until he injures Master Splinter out of rage. He is then sent to train with The Ancient One in Japan. He returns in Prodigal Son where Karai supposedly "killed" his family in Scion of the Shredder. Leonardo eventually rallies his family and finds a new lair. In the episode Outbreak, Donatello gets infected by a Monster, and mutates into one in Adventures in Turtle Sitting. In the Good Genes duo logy Leo, Raph, Mikey, Leather Head, and Splinter travel to Agent Bishop's base to demand a cure for their brother. After that the Turtles now go out on the rooftops again but are kidnapped by wooden ninja which expands in the next season.
Ninja Tribunal
In the fifth season, as he is a part of the eight acolytes under the Ninja Tribunal's training, Leonardo is the only one who doesn't receive a weapon from the Spirit Forge. The reason is unknown, but it's possible that while it saw him and Faraji as both worthy candidates, it sensed a greater force in Leo meaning he didn't need a weapon.
His otherworldly form is that of a dragon, a rare form, unheard of in someone his age. It could be a reason why the Spirit Forge didn't give him a weapon, and Kon, of the Tribunal, mentioned that he and the rest of the Tribunal were right about Leo, meaning they could have known he was given a great power that meant he didn't need a weapon. It is shown destroying evil guarding the second artifact with its ki alone. This avatar is first shown in More Worlds Than One. His brothers later exhibit dragon avatars as well. In the fifth episode Beginning of the End, he is given the sword Gunshin by the dying Faraji Ngala. He returns Gunshin in episode 12 Enter the Dragons, Part 1 when Faraji returns to help battle the Tengu Shredder.
Fast Forward
In the Fast Forward season, and the Back to the Sewer season, the damage that occurred to Leonardo's shell as stated above has somehow been repaired. Leo, Splinter, and his brothers are sent to the future by Cody Jones and Leo often calls Cody "little ninja". Leo still remains the most skilled. However, he does not play as big a part in this season as in the previous five. He is still the level-headed eldest brother.
In one episode focusing on Leo, Darius Dun, Cody's uncle, made dangerous clones of the Turtles designed to kill them. In a fight, Leo's clone is hit with a laser by Donatello's clone. He is knocked unconscious and the Turtles take him in (under security precautions, of course). Leo gives his clone a chance to redeem himself and join Leo and his brothers, but the clone betrays their trust and runs away. However, it is later shown that Leo's words have had an effect on the clone, who now wants the other clones to stop living like animals and share, as Leo, Raph, Donnie, and Mikey have taught him.
Back to the Sewer
In the Back to the Sewer season, Leo and his brothers must find Master Splinter's data bits after Viral blasted him apart into Cyberspace. At the end of the series, Leo helped get Splinter back and goes to Casey and April's wedding. After that, Leo and his brothers battle the Cyber Foot and defeat the Cyber Shredder. Leo also sees Casey and April get married after all the Foot Ninja and the Cyber Shredder are defeated. Leo is still the most skilled in combat despite the fact that he did not kill the Cyber Shredder.
As in the previous season, he does not play the lead part in this season. He mostly serves as a support character for Donatello's role.
Skills, Powers, and Abilities
Leonardo is extremely skilled and is very effective with his swords. He displays balance in physical strength and mental strength. He is the most responsible as he has to obey Master Splinter and keep an eye on his brothers.
Weapons
Leonardo primarily fights with his twin katana swords, but has used shurikens, grappling hooks, and those of his brothers.
Relationships
Family
Donatello
Leonardo and Donatello have been shown to get along well. Leo knows the value of Donnie's intelligence and like all of his brothers, he often relies on his engineering skills to get them through any situation. Leonardo and Donatello rarely argued in this series.
Raphael
Raphael and Leonardo can be competitive and butt heads at times, but other times the two have shown to care about each other, and will help each other.
Michelangelo
Like Donatello and especially Raphael, Leonardo gets really annoyed with Michelangelo’s pranks and wisecracks, and scolds him for his lack of focus but does show love towards his little sibling.
Master Splinter
Leonardo is the closest turtle to Master Splinter and his loyal to him. He knows what master Splinter expects of him and will do anything to meet his expectations.
Trivia
- Like his brothers, Leo is a practitioner of Chi Gong, as shown in Turtles in Space, Part 3: The Big House.
- In the season 3 finale episode, he was stabbed in the shoulder. In early season 4, when his bandages were removed, it was revealed that a portion of his shell had been hacked off too.
- Occasionally the damage on his shell would disappear, this can largely be attributed to animation errors.
- Has expertise in blacksmithing, as he was able to forge new katanas with the help of only Raphael in The Monster Hunter.
- He sometimes rides a foot-propelled scooter.
- Leonardo has been shown to be somewhat naive, when he ignores Raph's skepticism and trust enemies such as Shredder and Karai.