Hill died at a Pacific Palisades care facility after a long battle with Alzheimer's disease, said friend Walter Seltzer.
Hill was a well-known face on TV, appearing on "Alfred Hitchcock Presents," "The Defenders," "Ben Casey," "The Untouchables," "The Nurses," "The FBI," "Mission Impossible," "The Fugitive" and "Marcus Welby, M.D."
He was the star of "Owen Marshall, Counselor at Law" from 1971 to 1974.
Hill also appeared in the films "Harper," "The Ugly American," "The Andromeda Strain" and "A Bridge Too Far."
Born Aug. 1, 1922, in Melfort, Saskatchewan, Canada, Hill served in the Royal Canadian Air Force and attended the University of British Columbia.
He moved to Great Britain in 1948 where he performed in a variety of stage productions, then he moved to New York 10 years later and established himself on Broadway.
Hill made his Broadway debut opposite Ruth Gordon in "The Matchmaker," then went on to star in such stage hits as "Look Homeward Angel."
The actor won Tony and New York Drama Critics awards for his role as George in "Who's Afraid of Virginia Woolf" in 1962.