He won praise in both comedic and dramatic parts in Joe (1970), The Candidate (1972), The Friends of Eddie Coyle (1973), Taxi Driver (1976), F.I.S.T.

After graduating from high school in 1953, Boyle spent three years in formation with the De La Salle Brothers, a Catholic teaching order.

He lived in a house of studies with other novices earning a Bachelor of Arts degree from La Salle University in Philadelphia in 1957, but left the order because he did not feel called to religious life.

[10] After graduating from Officer Candidate School in 1959, he was commissioned as an ensign in the United States Navy, but his military career was shortened by a nervous breakdown.

[7] In New York City, Boyle studied with acting coach Uta Hagen at HB Studio[11] while working as a postal clerk and a maitre d'.

[citation needed] Boyle gained acclaim for his first starring role as the title character, a bigoted New York City factory worker, in the 1970 movie Joe.

Boyle received his first Emmy nomination for his acclaimed dramatic performance in the 1977 television film Tail Gunner Joe, in which he played Senator Joseph McCarthy.

His roles include the philosophical cab driver Wizard in Martin Scorsese's Taxi Driver (1976), starring Robert De Niro; a bar owner and fence in The Brink's Job (1978); the private detective hired in Hardcore (1979); the attorney of gonzo journalist Hunter S. Thompson (played by Bill Murray) in Where the Buffalo Roam (1980); a corrupt space mining-facility boss in the science-fiction film Outland (1981), opposite Sean Connery; Boatswain Moon in the (1983) pirate comedy Yellowbeard, also starring Cheech and Chong, Madeline Kahn, and members of the comedy troupe Monty Python.

In 1984, he played a local crime boss named Jocko Dundee on his way to retirement, starring Michael Keaton in the comedy film Johnny Dangerously, a psychiatric patient who belts out a Ray Charles song in the comedy The Dream Team (1989), also starring Michael Keaton; a boss of an unscrupulous corporation in the sci-fi movie Solar Crisis (1990) with Charlton Heston and Jack Palance; the title character's cab driver in The Shadow (1994), starring Alec Baldwin; the father of Sandra Bullock's fiancée in While You Were Sleeping (1995); the corporate raider out to buy Eddie Murphy's medical partnership in Dr. Dolittle (1998); the hateful father of Billy Bob Thornton's prison-guard character in Monster's Ball (2001); Muta in The Cat Returns (2002); and Old Man Wickles in the comedy Scooby Doo 2: Monsters Unleashed (2004).

Also in 1980, he co-starred with Tommy Lee Jones in an off-Broadway production of playwright Sam Shepard's acclaimed True West.

Two years later, Boyle played the head of a dysfunctional family in Joe Pintauro's less well-received Snow Orchid, at the Circle Repertory.

The comedy drama followed the life of a lonely, world-weary, and sometimes compromised New York City beat cop, whose closest friend was a prostitute, played by actress DeLane Matthews.

In the episode, "Clyde Bruckman's Final Repose", he played an insurance salesman who could see selected things in the near future, particularly others' deaths.

[23][24] At the time of his death, he had completed his roles in the films All Roads Lead Home and The Santa Clause 3: The Escape Clause—the latter being released one month before his death—and was scheduled to appear in The Golden Boys.

Ray Romano was personally affected by the loss, saying, "He gave me great advice, he always made me laugh, and the way he connected with everyone around him amazed me."

Springsteen segued into "Jungleland" in memory of Boyle, stating: "An old friend died a while back – we met him when we first came to New York City... Today would have been his birthday.

[28] Boyle's closest friends, family, and co-stars have since gathered yearly for a comedy celebration fundraiser in Los Angeles.