As part of the Royal Canadian Air Force during World War II, Hill served in the mechanic corps.

In 1956, he appeared as an accused murderer in episode 17 of Colonel March of Scotland Yard, an English/American production starring Boris Karloff.

Hill's Broadway theatre debut was in the 1957 revival of Thornton Wilder's The Matchmaker, playing Cornelius Hackl.

In 1963, Hill received the Tony Award for Best Dramatic Actor for his portrayal of George in the original Broadway production of Who's Afraid of Virginia Woolf?

Other Broadway credits include Ben Gant in the original production of Look Homeward, Angel (1957), All the Way Home (1960), Something More!

Other film work includes The Ugly American (1963), Harper (1966), Petulia (1968), The Chairman (1969), The Killer Elite (1975), Futureworld (1976), an uncredited role in A Bridge Too Far (1977), and narration of Something Wicked This Way Comes (1983).