In the Mirage comics all four turtles wear red bandanas, but in mainstream versions, he wears a blue bandanna. His signature weapons are two ninjaken (literally "ninja sword"), which are universally referred to as katana. Throughout the various media he is depicted as the leader of the four turtles and the most disciplined. He is named after Leonardo da Vinci.
Leonardo is depicted as the eldest brother and (along with Donatello) the calmest of the four. He never explicitly referred to himself as leader in the early stories, except issue #42 ("The Violent Underground"). He is the one to usually take charge of the turtles when Master Splinter is not present. He is often at odds with his more hot-headed brother, Raphael.
In Leonardo #1, Leonardo goes out for a run on the rooftops of New York City and is ambushed by the Foot Clan. He puts up an admirable fight against an army of Foot Ninja, but is eventually overwhelmed by them. Beaten to near unconsciousness, he is thrown through April O'Neil's apartment window. The remaining Turtles and Splinter are forced to continue the fight, but even with the aid of Casey Jones (Teenage Mutant Ninja Turtles), the odds are against them. In the end, Shredder presumes them all dead, but they secretly escape to Northampton.
During this time, Leonardo recovers from his physical wounds. However, he has lost a great deal of confidence. He repeatedly attempts, unsuccessfully, to hunt for deer. While out hunting, he sees April fall through ice into a lake, and he rescues her. In subsequent issues, it is implied that Leonardo has regained most of his confidence.
In the "Return to New York" storyline (Teenage Mutant Ninja Turtles (vol. 1) #19-21), Raphael demands that the Turtles return to New York to confront the Foot Clan and Shredder. He accuses Leonardo of cowardice, and the arguing brothers soon come to blows. Leonardo is beaten by Raphael, who throws Leonardo through the wall of the barn and leaves alone. Along with Donatello and Michelangelo, Leonardo returns to New York and reunite with their wayward brother in the old sewer lair. The three go along with Raphael's plan to storm the Foot Head Quarters, where once again Raphael goes off on his own to fight the Shredder. However, he is ambushed and beaten by Shredder's Elite guard, but is rescued by Leonardo. This prompts Raphael to finally cede to Leonardo's leadership, leaving him to fight the Shredder. Leonardo engages in a bloody battle with Shredder that spills out onto the rooftop of the building. Leonardo ends the battle by decapitating the Shredder just as the building implodes. The Turtles later burn Shredder's corpse in a funeral pyre in a nearby Manhattan harbor.
In the "City at War" storyline (Teenage Mutant Ninja Turtles (vol. 1) #50-62), a feud between various factions of the Foot Clan over leadership breaks out. As fighting ensures in the streets of New York, the Turtles and the civilian populace get caught in the middle. Leonardo grows weary of constant battle with the Foot Clan and seems fraught with indecision. The Turtles are approached by Karai, the leader of the Foot Clan in Japan who has come to New York to unite the Foot. She presents the Turtles with an offer of a truce between the Foot and the Turtles if they help her kill Shredder's Elite Guards, which are a major obstacle to her reorganizing the Foot. Leonardo persuades his brothers to accept Karai's offer (much to Raphael's chagrin) and all four Turtles successfully work with Karai to eliminate the Elite Guard.
Years later in Volume 4, Leonardo still leads his brothers (all four now in their thirties) in fights against crime. Leonardo and Raphael's conflict seems to have greatly lessened. When the Utroms make a very public arrival on Earth and reveal alien life to humans, however, the Turtles become free to mingle in everyday society. The Turtles also help the Utroms acclimate to life on Earth and work alongside the Foot Clan as security. One Foot Clan member is Cha Ocho, who Leonardo has a rivalry with due to an encounter years earlier. Karai approaches Leonardo for help when a mysterious force begins attacking various Foot Clans. (Only the New York branch is left intact.) His investigation takes him to the Battle Nexus, where he meets Oroku Yoshi (who wears armor similar to the Shredder's).
In Volume 3, Leonardo was initially portrayed as similar to his Mirage counterpart. (At the time, Image was picking up where Volume 2 left off.) In the later issues, he lost a hand, although this did not seem to deter him significantly. He tried initially to use a prosthetic hand, which was given to him by Donatello, but he much preferred to wear a steel cap which came with a retractable blade.
Volume 4 would later ignore all events in the Image series (though it is still referred to as "Volume 3").
The Archie Comics series initially began as an adaptation of 1987 animated series, so Leonardo was naturally portrayed like his animated counterpart. As the series progressed, it began telling original stories. Leonardo demonstrated a rather strong dislike for firearms. Also, a future version of Leonardo was depicted, having founded a ninja school. Four of his top students were depicted: Nobuko, possibly his love interest; Miles, a young black man; Carmen, a Latino woman; and Bob, an anthropomorphic baboon. These students seemed to have an "extended family" relationship with the Turtles, Bob in particular referring to them as uncles.
In the 1987 TV series' theme song lyrics, Leonardo is said outright to be the leader of the TMNT, and there is little disputing this; his orders are usually followed, and he is a very serious do-gooder who hardly ever makes wise cracks. In one episode, he suffered a crisis of confidence and left the group to do some soul searching; his brothers all tried their hands at being the leader in his stead, only to find that none of them could match his leadership skills, and he came back to them. He was attracted to a young kunoichi named Lotus, a swordswoman prodigy from Japan who was hired by Krang to replace Shredder, whom she easily defeated (along with Rocksteady and Bebop). She and Leonardo dueled to a standstill before she resorted to a trick sword to knock him out. When they met the second time, she tried to convince him to join her as "ninja for hire", but he refused. She turned on Krang and escaped to continue her mercenary lifestyle, telling Leonardo that there was little good in goodness, though she hoped that they would one day be on the same side. This is the only version of the TMNT mythos where Leonardo does not have his sibling rivalry with Raphael.
When the cartoon series starts out, he is shown with having a very level head, akin to his leadership qualities in the comic. However, as the series carried on, he became more reactionary and at times would screech in the very high pitched voice, which was very different from the original, deeper pitch in the first season. This presumably may have been the result of the writers downplaying Leonardo as a hero in favor of Michelangelo and Raphael, who were more popular with audiences.
Leonardo also seems to enjoy reading. For example, many times when the Turtles are at home, Leo is reading a book. In the episode Four Musketurtles, he is the only Turtle that read The Three Musketeers. Another good example is in "Leonardo is Missing"; while the other Turtles go to an arcade, Leonardo stays at the lair and reads.
In the season 3 episode "Take Me to Your Leader", Leonardo gives up his leadership and walks away after a dream he believes convinces him he is no longer a good leader. The others have to find him, and stop Shredder, Krang, and Bebop and Rocksteady from draining energy from the Sun with a Solar Siphon and store it in solar batteries. However, Leonardo returns when he spots a bridge collapsing due to snow. After a man says that everybody talks about the weather but nobody does anything, Leonardo realizes his responsibility and begins to search for his brothers. He later finds them, and together they save the Earth.
In the Season 6 episode "Snakes Alive", it is revealed that Leonardo has Ophidiophobia, but confronted it later.
This is seemingly the only incarnation of the TMNT in which Leonardo's swords are curved, possibly due to problems with animation, thus the term katana could be used.
In the original English language version of the 1987 cartoon show, Leonardo's voice actor was Cam Clarke (who also voiced Rocksteady). Leonardo is generally considered to be Clarke's "breakout role" and is still one of his best known parts. In the Hebrew language version, Leonardo was dubbed by Ido Mosseri. In the crossover movie Turtles Forever, this version of Leonardo is voiced by Dan Green. In the Finnish language version, he is voiced by Tom Wentzel.
Main article: Ninja Turtles: The Next MutationIn 1997-1998, Leonardo along with the other Ninja Turtles were featured in a short-lived live-action series. He also carried one double bladed ninjaken instead of two. His sibling rivalry with Raphael drove many episodes. In one episode where they were sparring, Raphael took advantage of Leo's apparent physical weakening, insulting, mocking and taunting his brother to make him more reckless, until finally Leo lost his temper and angrily kicked Raph so hard that he sent Raph flying across the sewer den. They spent the rest of the episode arguing and challenging each other to tests of skill (some of them quite absurd) until finally using arm wrestling to decide who would live in the sewer and who would leave. Although Leo won, it was decided that Raph should stay.
In the new Mirage Studios and 4Kids Entertainment 2003 animated TV series, Leonardo is voiced by Michael Sinterniklaas, while in the Japanese version, he is voiced by Tetsuya Kakihara. In the Finnish version, he is voiced by Samuel Harjanne (during seasons 1 and 2) and Markus Blom.
Leonardo is the de facto leader of the group and the most "spiritual" of the four. He has a very close bond with Splinter, and has a strong sense of honor, ethics, and Bushidō. Leonardo's twin swords are slung across his back. Episodes that deal with the Shredder and honor usually also focus on Leonardo, and he is often the Turtle who "saves the day." Leonardo is a more sensitive, self-doubting character than in previous incarnations. Raphael often quarrels with him and resents his leadership, sarcastically calling Leonardo "Fearless Leader", although the two are shown to be very close at times. Though Leonardo's relationships with his other brothers Michelangelo and Donatello are not as volatile, both have made comments alluding to the high standards the former has set, and his tendency to make them look bad. Despite this, 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).
At times, Leonardo is shown to be very hard on himself, as he feels that a lot is expected of him. As in the Mirage comics, Leonardo is ambushed and seriously injured by the Foot Clan and he feels he let his family and himself down. He has the same feelings after the final battle with the Shredder-his anger and self-doubt was caused by Karai, whom he believed was an honorable ally, but she was unable to go against her master's orders, eventually causing her to stab Leonardo (albeit unintentionally). Leonardo also feels extremely inadequate, as he believes that again, he let himself and his family down, this time by finding no other way to destroy the Shredder than to blow up the spaceship that both the Shredder and the Turtles were on; the Turtles and Splinter would have perished if they had not been rescued by Utroms. Eventually, Leonardo finds inner peace under the guidance of the Ancient One, who trained Splinter's sensei, Hamato Yoshi. From their final battle with the Shredder, Leonardo was the only Turtle to sustain truly lasting damage; part of his shell on his upper left shoulder had its edge shorn. Nevertheless, he is arguably the most skilled of the Turtles, being the only one trained by two senseis and is capable of facing and defeating Karai, the new Shredder, in a one-on-one fight.
Through much of the fourth season, Leonardo becomes increasingly stern. His brothers worry about him and Splinter feels he must move on. It comes to a head when Leonardo loses his temper and nearly causes Splinter serious injury during a training session. Splinter sends Leonardo find Master Yoshi's own sensei, The Ancient One. Leonardo encounters a strange short man, as well as obstacles that echo his own anger. In the end, Leonardo admits that he was angry over failing his family while fighting the Shredder and that his only option was to self-destruct the ship to stop him. Leonardo comes to terms with his anger and begins training under the short man, who turns out to be the Ancient One. Leonardo only leaves when he learns that his family is danger (a result of Karai's vengeance, which destroys the lair and presumably elminates them). Leonardo returns to the city, reunites his family in a safe location and battles Karai (giving her one last chance to leave the Turtles in peace).
In the fifth season, of the eight acolytes under the Tribunal's training, Leonardo is the only one who doesn't receive a weapon from the Spirit Forge. No real explanation is given for this, although it is possible that because his swords were reforged in Battle Nexus, he already possessed a weapon capable of fighting the Demon Shredder, thus he didn't need one from the Spirit Forge. His otherworldly form is that of a dragon, a rare form, unheard of in someone his age. It is shown destroying evil guarding the second artifact. 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" (one of the Fangs of the Dragon that commands the "White Flame of the Dragon King") by the dying Feragi. He returns Gunshin in episode 12 "Enter the Dragons" when Feragi returns to help battle the Shredder.
In the first three TMNT movies, Leonardo was fairly modest and sensitive, rarely issuing direct commands; he also joked around with his brothers much more than in other versions of the TMNT. It was he who first communicated telepathically with a kidnapped Splinter in the first movie, but he was not ambushed by the Foot Clan (Raphael was), nor did he kill the Shredder. However, he is the only one of the four Turtles to successfully injure Shredder during their climactic battle. He was acted by David Forman and voiced by Brian Tochi.
In both Teenage Mutant Ninja Turtles II: The Secret of the Ooze and Teenage Mutant Ninja Turtles III, his actor was Mark Caso and he was voiced again by Brian Tochi.
In the fourth TMNT film, Leo was sent away by Master Splinter to hone his skills in becoming a more efficient leader after Shredder's defeat. April finds him in Central America, and while he was hesitant to return to New York City, he does at the right time to take on the dangerous new force of evil.
His relationship with Raphael is strained due to Raphael feeling abandoned by Leo as well as feeling less appreciated by Splinter. Leonardo's vision of the world is perhaps wider than Raphael's; in the first movie prequel comic, Leo becomes angry with Raphael for trying to leave them in order to save a man from being mugged, because there are four heavily armed Triceratons in the sewers who could cause devastation to the city. He becomes further angered when Raphael deserts them mid-battle to help the old man. This conflict suggests that the two brothers operate on different levels of morality, though neither is necessarily wrong. Raphael states in the comic that he was tired of waiting for disaster to fall on his family, and tired of fighting aliens while people in their own neighborhood are being mugged and murdered. Leonardo, on the other hand, believes that the world of men is the responsibility of the police, while Utroms and Triceratons are their domain, and that they should fight only when there is no one else to solve the problem. This also engages Leo in a contradiction when he stays in Central America, using violence to fight local lawlessness and effectively deserting his brothers because he believes, as Raphael believes, that others need him more. Such parallels suggest that the two brothers are experiencing the same dedication to justice but in different mentality, albeit in very different locales and using different tactics.
In the TMNT CGI movie, Raphael challenges Leonardo after arguing of their own individual sense of justice and the reasons for their actions, Leo also discovers that Raphael is the Nightwatcher, and they engage in a fight. He is defeated when Raphael breaks his swords and pins him to the ground. Raphael almost kills Leo out of anger, then retreats due to his brother's deep and confused stare. Leonardo is captured by the War Generals and Foot Clan, but is rescued by his family later before the final battle where Leonardo and Raphael finally resolve their differences, Raphael accepting Leo as their leader while Leonardo confesses to needing Raphael. Leonardo is voiced by James Arnold Taylor in this film.
In the video games, Leonardo is the first turtle of choice. He is popular especially for beginner players of the TMNT games. Leonardo is portrayed as well-balanced, having, in all areas, strong but not extreme abilities and no glaring weaknesses. His range is rather long, but not as long as Donatello's; however, Leonardo can usually inflict more damage. In the Tournament Fighters games, his moves are the closest to a Ryu/Ken archetype from the Street Fighter franchise. He appears in Teenage Mutant Ninja Turtles: Smash-Up as a playable character, with Michael Sinterniklaas reprising the role.