Leonardo, often referred to as Leo, is one of the main protagonists of the 2012-2017 television series and the leader of the Ninja Turtles. He is also the oldest of the four brothers, who all share a home in the underground sewers of Manhattan, New York City. Leonardo is the adoptive son of Master Splinter and adoptive brother of Karai. He belongs to a diverse family consisting of three other mutant turtles who are his biological brothers: Raphael, Donatello, and Michelangelo. Splinter, a human-sized mutant rat, serves as the Turtles' adoptive father and sensei. This version of Leonardo was originally voiced by Jason Biggs from the series premiere until Season 2 Episode 19. Leo‘s voice sounded exactly like his age. Leo’s voice actor got temporarily recasted by Dominic Catrambone for the final 7 episodes of Season 2 (nonetheless, his voice still sounds very similar), and finally replaced by Seth Green from Seasons 3 to 5. With Green as Leo's third voice actor, Leo's voice becomes more adult like. His change of voice is explained by the character having wounded his larynx (vocal cords) in the aftermath of the battle in the Season 2 finale. Logan Lerman voice Leonardo Dylan Minnette voice Leonardo