Mark Caso

American actor, stuntman, and former competitive gymnast. He is best known for performing as the suit actor and stunt performer for Leonardo in Teenage Mutant Ninja Turtles II: The Secret of the Ooze (1991) and Teenage Mutant Ninja Turtles III (1993). Wearing a heavy animatronic suit, he executed the physical movements, martial arts choreography, and stunts for the TMNT leader across both live-action sequels. Prior to working in film, Caso was an elite gymnast and part of UCLA's 1984 NCAA championship team. This background allowed him to execute complex acrobatics and martial arts sequences despite the physical limitations of the turtle costume. While filming The Secret of the Ooze, he leveraged his championship gymnastics experience to execute Leonardo's back-handsprings directly rather than relying on a stunt double. In addition to suit acting, he made an unmasked on-screen cameo in the second film as a newsroom staff member notifying April O'Neil of a phone call from Donatello. Beyond his work in the TMNT franchise, Caso worked as a martial artist and stunt performer on other major productions. He served as the Sub-Zero stunt double in Mortal Kombat (1995), and doubled for characters including Raiden and Cyrax in Mortal Kombat: Annihilation (1997).