Rise to Fame
He spent the late 60s playing awkward, neurotic New Yorkers that Robert Altman seemed to collect. Bob & Carol & Ted & Alice (1969) got him an Oscar nomination, but it was Altman's M*A*S*H (1970) that put him on Time magazine's cover. He played Trapper John McIntyre as a loose, anti-authoritarian wiseguy in an anti-war satire that Hollywood desperately wanted to make but didn't quite know how. Time called him "a star for an uptight age," which was more accurate than most cover lines.
In the Spotlight
The early 70s peak didn't last. Drug issues and a string of commercial flops bottomed him out fast enough that the studio reportedly required a psychiatric evaluation before casting him in The Long Goodbye (1973). He staged two significant comebacks: a recurring role on Friends as Monica and Ross's dad (20 episodes across the run), then the Ocean's franchise through four films from 2001 to 2018. Most of his contemporaries faded out. He kept finding new rooms.
Side Notes
Born Elliott Goldstein in Brooklyn, he met Barbra Streisand during rehearsals for I Can Get It for You Wholesale in 1962. He had the lead. She had a minor role as a secretary and stole the show. They married secretly at a Carson City justice of the peace in 1963, and as her career exploded and his stalled, he reportedly resented being known as "Mr. Streisand." He later described the marriage as "a bath of lava." They divorced in 1971 but, by his own account, stayed genuinely close.