Perhaps most well known for his starring role in the John Cassavetes feature Faces, he is also famous for his portrayals of Jack Woltz in The Godfather and Phil Cavalleri in Love Story. His numerous television credits include guest spots on This Man Dawson, Dr. Kildare, The Twilight Zone, and Insight.
Early in his career, he acted in two episodes of the NBC series The Big Story.
A stage performer as well as a screen actor, he was in the cast of the original Los Angeles production and world premiere of the poetic Edna St. Vincent Millay play Conversation At Midnight.
Born Mortimer Marlieb, he spent his youth in New York, New York. His marriage to Stanja Lowe produced three children, including a son, Ben Marley, who became an actor.
He appeared with James Garner, John Lithgow, and Margot Kidder in the 1984 HBO movie The Glitter Dome.