Brian Dennehy, a versatile stage and screen actor known for action movies, comedies and classics, but especially for his Tony Award-winning performances in “Death of a Salesman” in 1999 and “Long Day’s Journey Into Night” in 2003, died on Wednesday in New Haven, Conn. He was 81.

His agency, ICM Partners, announced his death. His agent, Brian Mann, told The Chicago Tribune that the cause was cardiac arrest resulting from sepsis. Mr. Dennehy lived in Connecticut, where he was born.

Brawny and gregarious, Mr. Dennehy was often called on to play an Everyman or an authority figure: athletes, sheriffs, bartenders, salesmen and fathers. He was in scores of movies — “First Blood” (1982), “Gorky Park” (1983), “F/X” (1986) and “Presumed Innocent” (1990) were among them — as well as an assortment of television series. But his first love was always the stage.

“He was a towering, fearless actor taking on the greatest dramatic roles of the 20th century,” Robert Falls, artistic director of the Goodman Theater in Chicago, where Mr. Dennehy did some of his finest work, said in a phone interview. “They were mountains that had to be climbed, and he had no problem throwing himself into climbing them.”