Early life and television roles

O'Neill studied at Syracuse University.^[2] He served in the Navy then returned to the theater. In the late 1950s, he began appearing on television. His television credits include Car 54, Where Are You?, The Honeymooners, Barney Miller, Sanford and Son, Good Times, Kaz, M*A*S*H, The Feather and Father Gang,^[3] The Facts of Life, Family Matters, Mad About You, Murder, She Wrote, Father Dowling Mysteries, Three's Company, Wonder Woman, One Day at a Time, Magnum, P.I., A Man Called Intrepid, Growing Pains, Dark Justice, Cheers, Dharma & Greg, Cybill, The Fresh Prince of Bel-Air to Home Improvement. He was probably best known for his role as Charlie Cagney in the television series Cagney & Lacey. Before moving to California, he appeared on the Broadway stage in such plays as Promises, Promises, The Unsinkable Molly Brown, and Skyscraper.

Film roles

His film credits include The Mugger (1958), To the Shores of Hell (1966), Gammera the Invincible (1966), Pretty Poison (1968), Some of My Best Friends Are... (1971), The Taking of Pelham One Two Three (1974), The Front Page (1974), Posse (1975), St. Ives (1976), American Raspberry (1977), MacArthur (1977), The Buddy Holly Story (1978), House Calls (1978), The Jerk (1979), Wolfen (1981), Chiller (1985), Prizzi's Honor (1985), The Mosquito Coast (1986), She's Out of Control (1989) and Loose Cannons (1990).

Film

Television