He studied drama with actor Lee Strasberg for five years at the Actors' Studio in New York City.
One of his earliest works was with James Dean in A Rebel Without a Cause.
He was married five times to Brooke Hayward, Michelle Phillips, Daria Halprin, Katherine Lanasa, and Victoria Duffy. His marriage to Michelle lasted for two weeks. He has four children: Henry, Ruthanna, Marin and Galen.
He used to be good friends with Viggo Mortensen.