Martin Balsam won Best Supporting Actor for A Thousand Clowns and worked constantly as a character actor for four decades.
Psycho gives him the detective Arbogast, whose death on the staircase is the film’s second shock and required a complex process shot that Hitchcock spent considerable effort on.
12 Angry Men, All the President’s Men and Catch-22 fill out the serious work, and he was among the original members of the Actors Studio.
Little Big Man gives him a snake-oil salesman who loses a body part in every scene he appears in, which is a very strange running joke.