Daniel Louis Castellaneta is an American actor, comedian, and screenwriter. Castellaneta is best known for his work as Homer Simpson's voice actor, as well as the voices of other Simpsons characters such as Abraham "Grampa" Simpson, Barney Gumble, Krusty the Clown, Sideshow Mel, Groundskeeper Willie, Mayor Quimby, and Hans Moleman in the animated television series The Simpsons.