Mr. Dysart won a 1992 Emmy Award for playing another flawed authority figure, senior law partner Leland McKenzie on TV's "L.A. Law."
In the early days of Off-Broadway, he appeared frequently at the Circle in the Square Theatre, including its landmark production of The Iceman Cometh. He lived for a time in San Francisco in the 1960s. He became a founding member of San Francisco's American Conservatory Theatre, where he played the leads in classic plays, including Willy Loman in Death of a Salesman.
Mr. Dysart played Horace Giddens in the 1967 Broadway revival of The Little Foxes, directed by Mike Nichols.
His award-winning performance in That Championship Season was his last for Broadway. He worked in movies and TV for most of the rest of his career, earning four Best Supporting Actor Emmy nominations, and winning for "L.A. Law." Movie appearances include John Carpenter's "The Thing" and Clint Eastwood's "Pale Rider."