Daniel Louis "Dan" Castellaneta (born October 29, 1957) is an American film, theatre and television actor, comedian, voice artist, singer and television writer. Noted for his long-running role as Homer Simpson on the animated television series The Simpsons, he also voices many other characters on The Simpsons, including Abraham "Grampa" Simpson, Barney Gumble, Krusty the Clown, Groundskeeper Willie, Mayor Quimby and Hans Moleman..