Often shown wearing an ocean blue bandana, his signature weapons are a pair of swords (named katanas in many versions of the series).

Karai approaches Leonardo for help when a mysterious force begins attacking various Foot Clans; only the New York branch is left intact.

In the IDW-published conclusion, TMNT Urban Legends 25, after an altercation with Lady Shredder which smashed his steel cap beyond use, Leonardo's hand was found to have grown back.

In the Cityfall saga, he gets captured by the Foot while he and his brothers try to save Casey and is taken to a Shinto witch by the name of Kitsune, who uses her dark magic to brainwash him into working for Shredder as his chunin (second-in-command), which infuriates Karai.

In the lyrics for the 1987 TV series' theme song, Leonardo is stated to be the leader of the turtles; his orders are usually followed, and he is a serious do-gooder who does not joke around.

He was attracted to a young kunoichi named Lotus, a swordswoman prodigy from Japan who was hired by Krang to replace Shredder, whom she defeated (along with Rocksteady and Bebop).

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.

His brother 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 younger brothers Donatello and Michelangelo 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.

Because of what happen in the last battle against the Shredder, Leo becomes bitter and increasingly stern with himself and adopts a greatly aggressive personality, which has been likened to Raph's previous impulsive and hotheaded ways on many occasions.

Leonardo also shows considerably less reluctance in using violence to interrogate people, and devotes himself to even greater lengths of training in order to protect his family.

Not wanting to worry his family, Leonardo decided to not tell them about his true feelings about their final battle against the Shredder, although he open up to April and Usagi about his problems.

From their final battle with the Shredder, Leonardo was the only Turtle to sustain truly lasting damage; part of the shell on his upper left shoulder had its edge shorn.

In this latest version, Leonardo seems to be less experienced and still perfecting his fighting skills and leadership abilities to make more solid decisions and gain more trust from his three brothers.

Leonardo's weapons here are purely dual katanas, which he uses in the Niten Ryu style of kenjutsu, making him an excellent swordsman.

In the 2018 animated series, Rise of the Teenage Mutant Ninja Turtles, "Leonardo, the self-professed "coolest" brother possesses irreverent charm and a rebel heart".

[3] Unlike past versions, he is not the official leader of the turtles until the second season finale, and boasts a less serious, more laidback, charming, sardonic, and joke-cracking personality.

In Rise of the Teenage Mutant Ninja Turtles: The Movie, Leo ends up doing more harm than good when his ego causes an alien race called the Krang to invade and Raphael to be captured.

In Teenage Mutant Ninja Turtles, Leonardo was fairly modest and sensitive, rarely issuing direct commands and seemingly much more relaxed around his brothers thinking of himself as more of an equal than a leader.

Due to the focus on Raphael in the film's plot, Leonardo's personality was rarely explored and his leadership position in the team took a back seat.

This time, Leonardo was portrayed by Mark Caso and once again voiced by Brian Tochi In Teenage Mutant Ninja Turtles III, after traveling back in time to feudal Japan, Leonardo leads his brothers to help a village in trouble from the villainous weapons trader, Walker, and to return home.

In the last of the original film's trilogy, Leonardo was once again portrayed by Mark Caso and voiced by Brian Tochi In TMNT, Leo was sent away by Master Splinter to hone his skills in becoming a more efficient leader after Shredder's defeat.

In the first movie prequel comic, Leo becomes angry with Raph for trying to leave them in order to save a man from being mugged because 4 heavily armed Triceratons in the sewers could cause devastation to the city.

Leo, on the other hand, believes that the world of men is the responsibility of the police, while Utroms and Triceratons are their domain... that they should fight only when there is no one else to solve the problem.

[4][5] Leonardo appears in Teenage Mutant Ninja Turtles, portrayed by Pete Ploszek in motion capture and voiced by Johnny Knoxville.

[9] Leonardo appears in the direct-to-video crossover film Batman vs. Teenage Mutant Ninja Turtles, voiced by Eric Bauza.

He appears in Teenage Mutant Ninja Turtles: Smash-Up as a playable character, with Michael Sinterniklaas reprising the role.

Leonardo is one of the main playable characters in Teenage Mutant Ninja Turtles: Out of the Shadows video game, where he is voiced by Scott Whyte.

Leonardo is featured as one of the playable characters from Teenage Mutant Ninja Turtles as DLC in Injustice 2, voiced by Corey Krueger.

This is the second official Teenage Mutant Ninja Turtles game in which he is played by his original voice actor, Cam Clarke.