Leatherhead appears in the 2012 TV series. He is an ally to the Turtles and has also become Slash's second-in-command in the Mighty Mutanimals. In this series, Leatherhead made his debut appearance in the episode It Came From The Depths. He is voiced by Peter Lurie.
Leatherhead is, overall, a rather heroic character with good intentions, but he can be dangerously unstable thanks to the Kraang's cruelty to him since he was flushed in the sewers and captured by them. Simply mentioning the word "Kraang" causes him to lose control and he is sent on a violent rampage. When he regains his senses, he is often horrified by what he's done and so he tries to isolate himself from others. Leatherhead seems to find himself unbearable to live with, and he would prefer to live a secluded life.
Despite his temperamental side, Leatherhead also has a calm side that is very kind, gentle, sensitive, loving and affectionate. Leatherhead spends most of his time alone, and he uses candles and soothing music to restore a useful calm. But since he has befriended the Turtles, his time spent with Michelangelo in particular is another potent calming influence, for which Leatherhead is very grateful. Leatherhead has proven to be a strong ally and a friend to the Turtles.
Since returning to Earth after the decades Leatherhead spent trapped in Dimension X, Leatherhead is still a fierce fighter, but has never been shown losing control of his emotions anymore, having changed from an unstable volatile personality to a personality more stable than those around him. He befriends Slash, becoming the brother figure the turtle always wanted (aside from Raph). Leatherhead also functions as Slash's reliable second-in-command of the Mighty Mutanimals. In particular, Leatherhead has become a reassuring voice of moral wisdom, demonstrating this new-found capacity when Slash suffers moments of self-doubt.
When Leatherhead was a normal baby alligator, a human boy kept him secretly as a pet. One day, the boy's parents discovered him and forcefully flushed the baby alligator down the toilet into the sewers. After this, the Kraang found Leatherhead and took him back to their home dimension, where they performed horrid mutagen experiments on him. They either purposely or unintentionally changed him into an intelligent and strong, but monstrous mutant. However, in spite of this, Leatherhead's spirit remained unbroken.
One day, Leatherhead was able to break free and escaped back to his own dimension in New York. Six months before meeting the Turtles, Leatherhead stole a Power Cell — a piece of technology the Kraang need to control their dimensional portal. They chased and hunted him down to get the power cell back, and they eventually cornered him in the sewers under New York City. Leatherhead refused to surrender the power cell and defeated many of the Kraang-droids in battle, but was subdued by electrocution. While he was unconscious, the Turtles came to his side and defeated the remaining Kraang-droids. At Mikey's insistence, they took him back to the lair with them.
When Leatherhead awoke in the lair, he momentarily believed that the Kraang were still attacking him. He immediately grabbed Donnie and attacked the turtles, but was knocked out again when Leo electrocuted him with a stun gun. Leatherhead woke up some time later - and would have harmed Mikey if not for the chains restraining his arms. After calming down, he began to trust Mikey enough to eat his cooking and let him give him a name. Leatherhead also told him that he did not mean to attack the Turtles earlier, but he cannot control himself when he enters that aggressive state and he is always ashamed of himself afterward.
By the time Leo, Raph, and Donnie return to the lair with the power cell, Leatherhead had calmed down enough so that Mikey could remove his chains. They tried to ask him about the power cell, but they quickly found out that mentioning The Kraang caused Leatherhead to become violently angry. He blindly attacked the Turtles, including Mikey. Splinter intervened, managed to defeat Leatherhead in combat, and drove him out of the lair. Leatherhead took the power cell with him as he left, unaware that Mikey was following him.
Leatherhead retreats to his own lair, a graffiti-covered subway car. He plays an old vinyl jazz record that seems to calm his rage. Mikey comes in and demands an explanation for his actions. Leatherhead reminds him that he must be alone, as there is a dangerous force within him. Mikey's brothers soon arrive and command Leatherhead to leave Mikey alone. Leatherhead pleads that he means Mikey no harm and he tells The Turtles the story of his past - how he stole the power cell, and why the Kraang need it so badly.
Just then a squad of Kraang droids attack the subway car. The Turtles defend Leatherhead the best they can, but there are too many and they can't hold them off for long. Leo suggests Donnie use the power cell to get the subway car mobilized. Leatherhead entrusts Mikey with the cell and confronts The Kraang to buy Donnie some time. Leatherhead decimates The Kraang forces, and Donnie manages to hook the power cell to the subway car's motor and the Turtles escape.
After the battle, two surviving Kraang attempt to regroup and warn their allies that the turtles escaped with the power cell, only for Leatherhead to confront them, assuring them that they would not be telling anyone anything. With a rumbling roar, the huge reptile lunged at them with his jaws wide open, suggesting that he killed the two aliens.
Leatherhead appears again in TCRI. The Turtles have lost the precious power cell to the Kraang. Leatherhead had trusted that they would keep the cell, so Leo suggests that they should pay Leatherhead a visit, in order to solve the problem. Leatherhead awakens, but the turtles still had to tell him about the loss of the cell. Donnie informs them that Leatherhead will attack, but Leatherhead is able to calm himself when Mikey tells Leatherhead who they are once again. Leatherhead reports to them that all he remembered was a logo that the Kraang could operate under, and Donnie is able to track that logo to the T.C.R.I. work center in Brooklyn. The building had been the main base of the Kraang. The turtles have to investigate the building and stop the portal from being activated. Leatherhead helps them break into the building and he fights the Kraang-droids while the Turtles go to the top floor. By the time Leatherhead catches up with them, they are fighting Traag, a gigantic monster that came through the portal to Dimension X. All seems lost until Leatherhead arrives and joins the fight. He grabs Traag by the feet and throws him towards the portal. However, Traag is not still not defeated, and in spite of Mikey's protests, Leatherhead says farewell and pulls Traag into the portal with him, and they both disappear into Dimension X.
Leatherhead "appears" in Mazes & Mutants, but not as himself. When a Mutant Sparrow named Sir Malachi tricks the Turtles into playing an illusionary world created by their board game, Sir Malachi uses Leatherhead's likeness as the Dragon that guards Princess April from the Turtles. Acting as Sir Malachi's dragon, this illusion of Leatherhead could breath fire and possesses none of his personality traits except for his ferocity. Later after the Turtles expose Sir Malachi's illusions as being false, the illusion of Leatherhead (along with Dr. Tyler Rockwell as "Monkey Goblins") is seen following Sir Malachi as they leave the Sewer.
In Into Dimension X, Leatherhead has grown a few decades older - his scale color changing from green to grey due to Dimension X's different quantum physics and time differential. Stealing a communication orb, Leatherhead managed to send a warning to the Turtles that the Kraang had perfected the mutagen and were planning to invade. However, he was cut off and recaptured by the Kraang and subjected to torture. Eventually, he was rescued by the Turtles. As the Kraang began to initiate the invasion of Earth, Leatherhead believed that they should go down fighting, whilst Donnie believed in fleeing. However, Mikey came up with the plan to sabotage the portals, telling Leatherhead to crush the Kraang while leaving only one back to Earth for them to escape before destroying the Kraang base behind them. Once the portals were deactivated, Leatherhead wanted to guard the Turtles' escape but Mikey refused to leave him behind again and kicked him through the portal. Leatherhead returned to his dimension and caught the turtles as they fell. He subsequently agreed to join them in fighting the invasion, which is bound to occur.
In The Invasion, Part 2, Leatherhead showed up to save Splinter from nearly getting killed, first by some of the Kraangdroids where they teamed up to find the turtles. Before Splinter is about to be killed by Shredder, Leatherhead grabs him in his mouth and thrashes him around. Despite catching Shredder off-guard, when he tends to Splinter, Shredder uses this time to ultimately brutally injure Leatherhead and knock him onto a platform in a construction site surrounded by water, which collapsed under his weight. His fate after this has not been explained.
In Battle for New York, Part 1, he reveals that he survived his supposed death from the Shredder in The Invasion, Part 2 as he is first seen alongside The Mighty Mutanimals as they rescue the turtles from the Kraang after they save two humans who they found, captured and were preparing to mutate. He is then hugged by Mikey who he helps defend Slash from Leo as they state that everyone deserves a second chance. they all then go back to their lair (unaware that the kraang are following them). back at their lair, they meet their benefactor; Jack J. Kurtzman (who reveals that he survived from the invasion). He then informs them about the Kraang's plan (which is to launch a giant rocket full of mutagen straight into the earth and mutate the entire planet) and tells them that they have to work together. everyone begins to fight when suddenly the Kraang break in and begin to attack them all. During the battle and much to everyone's despair, Jack is shot and injured while trying to retrieve a Intel disc with the information on it. Leatherhead then comes to his aid by carrying him and retreats with everyone back to Antonio's Pizza-Rama (the turtles temporary base). They then take the disc and decide to work together while arguing as they come up with a strategy attack on the kraang. They then show up at the launch site and begin to attack the Kraang (including Kraang Subprime who survived his supposed death in the invasion) which is a great distraction for the turtles who (using Donnie's latest invention "the Turtle Blimp") reach and try to disable the rocket. Despite their best efforts, Kraang Subprime manages to launch the rocket. Luckily Donnie is able to reset the coordinates and sends the rocket straight to the sun; with them gliding to safety in the process. The kraang then retreat and escape the area. They all then celebrate their victory and head to TCRI so they can enter Dimension X and rescue the mutated humans from the Kraang.
In Battle for New York, Part 2, he alongside The Mighty Mutanimals manage to get into the TCRI building and break into the room that contains the portal device. They then open the portal as they attack the Kraang only to get ambushed by Mrs. Campbell, some Biotroids and Irmabots. During the battle, Leatherhead is held down by some of the Biotroids. He along with the team are then captured and the portal is deactivated which leaves the turtles trapped on the other side. They are all then placed in a glass cell. Leatherhead then confronts Slash who has doubts about be the team's leader. They then escape the glass cell with help from Dr. Tyler Rockwell (who uses his telekinesis abilities) and begin to attack the Kraang again. This time they win the battle, reopen the portal and help the turtles de-mutate the humans and save everyone by teleporting them all back to earth. They then appear alongside the turtles on some rooftops after saving the city (with the humans de-mutated, saved and returned as well as the power being restored and the Kraang defeated). Mikey then gives Leatherhead another hug. They all then celebrate and shout "Booyakasha".
In Requiem, Leatherhead and the other Mutanimals team up with Karai and Shinigami to plan the attack on Super Shredder. When Shredder invades the building, Leatherhead is defeated by him and sets fire to the Mutanimals' lair. When Splinter, the Turtles, April, and Casey arrive, the teams are divided. Leatherhead, Leonardo, Michelangelo, and Donatello go to the Coney Island amusement park to fight against Shredder's henchmen. During the fight, Rahzar pins Leonardo to the ground, about to strike him, until Leatherhead tackles him off the pier into the water and drowns him very deep in the water.
In End Times
In The Big Blow-Out! he alongside Slash and Mondo Gecko catches Bebop and Rocksteady, who were sent by 80s version of the Shredder and Krang to steal the Kraang crystals, in the TCRI building but failed to stop them. Later, he and the rest of the Mutanimals joins the turtles, their 80s counterparts and April in fighting Traag and Granitor until Bebop and Rocksteady, who discovered a treacherous plan to destroy Earth, saves everyone in the city.
In battle, Leatherhead relies mostly on crude punches and powerful bites to subdue his opponents, but he also incorporates in his fighting style the characteristic spin move, referred by experts as a "death roll", that the crocodilian reptiles, like crocodiles or alligators, use to remove the meat from their prey. Usually, Leatherhead uses this movement to get rid of opponents clinging to his back or to crush them under his mighty weight. He is extremely strong and fast-moving, making him quite a dangerous adversary. He also has keen senses, a very tough hide and like all crocodilian reptiles is a good swimmer.
Friends / Allies
- Donatello - Nominally a friend and ally of Leatherhead's, along with the rest of the turtles. However, Donatello is the most wary of Leatherhead's violent tendencies. When Leatherhead has his fits of rage, he has a habit of reaching for Donatello's face and shaking his entire body like a rag doll. As such, their first few encounters are marked by great mutual agitation. Later, after Leatherhead was forced to abandon his subway car home, Donatello took the subway car with him and converted it into the Shellraiser. After being rescued from Dimension X, Leatherhead was never seen losing control of his temper again, much less grabbing Donatello by the face again.
- Jack J. Kurtzman - Sometime after the events of The Invasion, Part 2, Kurtzman became involved independently with the Mighty Mutanimals, of which Leatherhead became a member along with Slash, Pigeon Pete and Dr. Tyler Rockwell. Kurtzman was a noncombatant who assisted the Mighty Mutanimals using his expertise on the Kraang.
- Leonardo - Leatherhead considers him to be a friend and ally along with the rest of the turtles.
- Michelangelo - Leatherhead's most beloved friend, the two hit it off very quickly and came to share a loving bromance. Michelangelo was the first person since mutation ever to show Leatherhead compassion, even being the one who gave the alligator mutant his name. Since then, the two developed a strong mutual affinity and rapport. Michelangelo has proven to be one of the few influences that could calm Leatherhead down from his fits of rage and make him feel at ease. Indeed, they became extraordinarily affectionate and intimate, with Michelangelo giving Leatherhead massages and body rubs and even sleeping spooned together on the Living Room floor. In TCRI, when the Turtles saw Leatherhead again for the first time in the episode, Michelangelo immediately reacted with love at the sight of Leatherhead sleeping. Later in this episode, Leatherhead became stranded in Dimension X, and the two would not meet again for an entire season. Later in Into Dimension X! after the long-imprisoned Leatherhead managed to send a message through a portal to the turtles, Michelangelo was shown to strongly love and miss Leatherhead in a series of tender sepia-toned flashback scenes, and he impulsively leapt into Dimension X to rescue him. This reunion was short-lived, as Leatherhead soon went missing again during The Invasion, Part 2 and neither he nor Splinter joined the others who fled to the O'Neil Farm. Mikey and Leatherhead met again in Battle for New York, Part 1 and Battle for New York, Part 2, with their mutual affection undiminished as they shared tender loving embraces in three separate scenes over course of the two-part episode's events. In Clash of the Mutanimals, when a beaten Leatherhead rushed to the Turtle Lair, Mikey caringly called him "adorable yet tortured". Leatherhead is one of the few people to consistently call Michelangelo by his full five-syllable name, rather than just "Mikey."
- Pigeon Pete - Pigeon Pete and Leatherhead first met sometime after the events of The Invasion, Part 2, when they formed the Mighty Mutanimals along with Slash and Dr. Tyler Rockwell and the cooperation of Jack J. Kurtzman.
- Raphael - Leatherhead considers him to be a friend and ally along with the rest of the turtles. When the turtles first encountered Leatherhead and Michelangelo felt compassion for him, Raphael was originally vocally opposed to bringing Leatherhead back to the Turtle Lair, but he eventually grew on him.
- Dr. Tyler Rockwell - Dr. Rockwell and Leatherhead first met sometime after the events of The Invasion, Part 2, when they formed the Mighty Mutanimals along with Slash and Pigeon Pete and the cooperation of Jack J. Kurtzman.
- Slash - Slash and Leatherhead first met sometime after the events of The Invasion, Part 2, when they formed the Mighty Mutanimals along with Pigeon Pete and Dr. Tyler Rockwell and the cooperation of Jack J. Kurtzman. In Battle for New York, Part 1 and Part 2 Leatherhead was Slash's second-in-command and friend who provided him with level-headed moral counsel. Slash addresses Leatherhead as "brother," similarly to the Newtralizer before him, implying that, in Leatherhead, Slash finally found the brother figure he had longed for.
- Splinter - A friend and ally of Leatherhead's. In The Invasion, Part 2, Leatherhead arrives to join Splinter in a fight against pursuing Kraangdroids, and calls Splinter his friend. They later fight the Shredder together as comrades. Leatherhead also was shocked at Splinter's death and was present at his funeral, mourning his friend’s death.
- The Kraang - Leatherhead's archnemesis. In Leatherhead's youth, after he was flushed down the toilet, he was taken and mutated by the Kraang, and horrifically experimented on, but eventually managed to escape. Leatherhead retains a great deal of loathing for the Kraang; even the very mention of them can automatically trigger one of Leatherhead's fits of rage. Leatherhead gained control of his rage triggers after decades trapped in Dimension X. Later, as part of the Mighty Mutanimals, Leatherhead was instrumental in expelling the Kraang from Earth.
- Shredder - An enemy of Splinter and the turtles makes him an enemy of Leatherhead. When Splinter became trapped underneath a pile of large pipes by the Shredder, Leatherhead came to Splinter's rescue and fought the Shredder. But the Shredder proved too quick for Leatherhead and eventually defeated him. Later, as part of the Mighty Mutanimals, Leatherhead joined forces with Leonardo, Donatello, Michelangelo and Pigeon Pete to rescue Slash, Dr. Tyler Rockwell and Raphael from the Shredder's mind control.
- In Leatherhead's first two episodes in the first season, every time he loses control of his anger around the Turtles, he tended to grab Donatello by the face and shake him like a rag doll.
- Leatherhead has a scar on the upper left side of his chest. He received it when he stole the power cell from the Kraang.
- When he is angry, Leatherhead's eyes are covered with white membranes, the nictitating membranes, that in normal alligators, crocodiles and relatives, protects the eyes when they are diving.
- His head looks much more like that of a crocodile than an alligator.
- Leatherhead's rollover is an actual crocodile/alligator movement known as the 'death roll'; it is something of a signature move that is primarily intended to tear their prey apart.
- In Into Dimension X!, it was revealed in one of Michelangelo's flashbacks that sometime in between the beginning of It Came From The Depths and Leatherhead's second appearance in TCRI, there was at least one time Leatherhead and Mikey slept together on the floor of the common area. This briefly-shown tepia-toned ambient-lit scene showed them both sleeping on their left sides against the floor grate, Mikey's back spooned into Leatherhead's front, with Leatherhead's long trail curled around Mikey's other side.
- Leatherhead was introduced with green scales, but since Into Dimension X!, his scales have gone grey from age. In the new opening sequence that premiered with the episode, Return to New York, Leatherhead is shown with his youthful green scales in the scene where he jumps from the rooftop of the Party Wagon to the rooftop of Bebop and Rocksteady's van. But when he makes his return episode appearance in Battle for New York, Part 1, his scales are still grey. Oddly enough, during the entire episode of "Requiem", his scales were green.
- The sound effects used for Leatherhead's roars and bellows do not always sound like those of real crocodiles and alligators.