His movie debut was in 1943's The North Star when he was 18.
Best known for his work in the Hitchcock movies Rope (1948) and Strangers on a Train (1951).
In 1953 he bought out the remaining two years of his contract with MGM so that he could pursue stage work, and in 1959 was on Broadway as Fitzwilliam Darcy in a musical version of Pride and Prejudice called First Impressions.
Also starred on Broadway with Julie Harris and Larry Hagman in 1959's The Warm Peninsula.
In 1986 he appeared on As the World Turns playing the role of Earl Mitchell, Lisa's husband. (Julianne Moore appeared on the soap at the same time, though their story lines were not linked.)
Appeared in a 1995 documentary about the history of homosexuality in the Hollywood film industry.
His romantic partners included soap star Jimmy Mitchell, Leonard Bernstein, Ava Gardner, Arthur Laurents, Shelley Winters ("the love of my life and the bane of my existence") and Robert Calhoun.
Said that of his partners, Gardner attracted him most.
Told Daily Intel that he considered himself neither gay nor bisexual: "We're not going to emerge as untarnished until we get rid of labels."
His last movie was 2002's The Next Big Thing.
His memoir, Include Me Out: My Life From Goldwyn to Broadway, was written with Calhoun and published in 2007.