The son of show business people, he studied theater at the American Academy of Dramatic Arts. He worked in stock, then in 1951 he debuted on Broadway in The Rose Tattoo. In 1952 he was drafted to fight in the Korean War, but he was exempted as a conscientious objector; instead, he worked with refugees. Not until 1955 did he return to acting, appearing in Broadway's The Skin of Our Teeth; Joshua Logan spotted him in the play, and signed him to appear in Bus Stop (1956), his screen debut; for his portrayal of a cowboy who romances Marilyn Monroe he received a Best Supporting Actor Oscar nomination. While making the film he met actress Hope Lange, and the two of them were married that same year; they divorced in 1961. With a few exceptions, his later screen roles were unrewarding, though he remained fairly busy through the mid '60s; he has continued appearing on screen intermittently. He has occasionally produced, directed, and/or co-written films. He starred in the late '60s TV series The Outcasts, and later costarred in the series Knots Landing. He is known as a highly principled man of strong social and political convictions.