In the first film, 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; he also joked around with his brothers much more than in other versions of the TMNT. Since the film was mostly based on the Mirage comics, one can best compare Leonardo's personality with his counterpart from the comics. He is rather quiet, always trying to put together a plan before he attacks and is again the one that is closest to Splinter. It was he who first communicated telepathically with a kidnapped Splinter in the first movie. In this version he clashes more often with Raphael, as they are just too different. Though they are basically still close as brothers. While he was not ambushed by the Foot Clan (Raphael was unlike the comics) he seems the most anxious about Raphael's health after his ambush by the Foot Clan. When Raphael was seriously injured Leonardo kept guard by his side day and night. He also did not kill the Shredder. However he fought alongside his brothers against The Shredder in the climactic battle, and he is the only one of the four Turtles to successfully injure the Shredder during their climactic battle, but, like his brothers, could not defeat him. Due to the focus on Raphael in the film's plot, Leonardo's personality was rarely explored and his leader position in the team took a back seat.
In the second film, Leonardo was much more prominent and his leader position was brought to focus. He is seen on many occasions bickering with Raphael as their sibling rivalry begins to become much more serious. He, like his brothers, was astonished at the return of the Foot but he found that their current homelessness due to their last battle was a more pressing issue and soon he convinced his brothers that they needed to move. Leonardo is once again sensitive, caring, and humorous in this adaptation but he now displays far more aggressive leadership tendencies.
In the third film, Leonardo helps his brothers back in feudal Japan to go back home after helping a village in trouble from the greedy-western-colony driven man, Walker. Leonardo at this point in the movie series had become less and less of a leader, shouting out wise cracks and goofing off with his brothers, a flaw not present in other incarnations of Leonardo. He was the one who defeated Lord Norigana by trapping him within a Japanese Bell before cutting his pony tail off mocking him about a new haircut. Like his brothers minus Donatello, he seemed at home in ancient Japan. In this film there wasn't much for him to really do, he was just portrayed as a goofball making only a few smart decisions.April finds him in Central America, and once again, Leonardo's desire for perfection was shown, as even as his real training was over for a year, he didn't want to return because he feared he may still not be good enough. 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 Leonardo 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, Leonardo 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. Leonardo also discovers that Raphael is the Nightwatcher and they engage in an emotional fight. He is defeated when Raphael breaks his swords and pins him to the floor. Raphael almost kills Leonardo out of anger, then retreats in horror of his own actions due to shame, remorse for his actions, and his brother's deep and confused stare. Leonardo is captured by the Stone Generals and Foot Clan, but is rescued by his family later before the final battle where Leonardo and Raphael finally resolve their differences. Raphael accepts Leonardo as their leader while Leonardo confesses to needing Raphael. In the end he realized that he can do anything if he has his brothers by his side.
- According to the T files on the DVD extras of the 1990 film, Leonardo's:
- Hobbies are collecting candles, if it counts.
- Favorite music is Traditional Japanese, and New Age (for meditating).
- Favorite foods are pizza, rice, fish, sushi, and apples.
- Favorite book is On the Art of War by Sun Tzu.
- Favorite color is blue.
- Is right-handed.
- Height is 5'1.
- Weight is 170 lbs.
- Eyes are brown.