in Batman: Under the Red Hood John DiMaggio was what fictional supervillain created by Bill Finger
Batman: Under the Red Hood:  The film stars Bruce Greenwood as Bruce Wayne/Batman, Jensen Ackles as the Red Hood/Jason Todd, John DiMaggio as the Joker, Neil Patrick Harris as Nightwing/Dick Grayson, Jason Isaacs as Ra's al Ghul, and Wade Williams as Black Mask. Joker (character): The Joker is a fictional supervillain created by Bill Finger, Bob Kane, and Jerry Robinson who first appeared in the debut issue of the comic book "Batman" (April 25, 1940), published by DC Comics.
Joker