Comedian and actor who won an Academy Award for Best Supporting Actor for his role in the 1997 film Good Will Hunting. He also played lead roles in the films Dead Poets Society, Hook, Mrs. Doubtfire, Patch Adams, Jumanji and Good Morning, Vietnam and he voiced the genie in the Aladdin films.
He attended Juilliard Drama School alongside good friend and fellow actor Christopher Reeve. He had his breakthrough role as a comic actor in Mork and Mindy.
He portrayed Teddy Roosevelt in the Night at the Museum films.
His daughter Zelda Rae Williams became an Actress and he also had two sons named Zachary and Cody. He was married to Valerie Velardi from 1978 to 1988, Marsha Garces from 1989 to 2010 and Susan Schneider from 2011 to 2014.
He starred as Peter Pan alongside Julia Roberts in the adventure film Hook.