Kevin Conroy and Mark Hamil talk to a standing room only panel at the Toronto Fan Expo 2016 about their careers in voice acting as Batman and the Joker.
Mark Hamil Solo Panel: https://www.youtube.com/watch?v=jIE2RTtIp6U&t=2525s
Hamill is a prolific voice actor who has voiced characters in many animated television shows, movies, and video games since the 1970s. He is known for his long-standing role as DC Comics’ the Joker, commencing with Batman: The Animated Series in 1992 as well as Skips from the Cartoon Network series Regular Show.
Due to the popularity of his performance as Batman, Conroy went on to voice the character for multiple films under the DC Universe Animated Original Movies banner and various video games; including the acclaimed Batman: Arkham series.
Mark Hamil: https://en.wikipedia.org/wiki/Mark_Hamill
Kevin Conroy: https://en.wikipedia.org/wiki/Kevin_Conroy
Star Wars: https://en.wikipedia.org/wiki/Star_Wars
Batman: The Animated Series: https://en.wikipedia.org/wiki/Batman:_The_Animated_Series