Coyne was born in Chicago, Illinois. At age ten he began working as a caddie at Midlothian Country Club. Both his parents were from the west of Ireland; his father was from a remote area, and had spoken only the Irish language until he was about twelve. As a result, Coyne grew up with bedtime stories of Ireland, on which he would later draw for his Dungeons and Dragons-influenced novel Hobgoblin.
After graduating from Saint Louis University, he earned a master's in English at Western Michigan University, served in the Air Force, and served in the Peace Corps from 1962 to 1964, teaching English at the Commercial School in Addis Ababa, Ethiopia. He currently lives in Pelham Manor, New York, with his wife and son, where he works in communications and edits PeaceCorpsWriters.org.
Coyne became one of modern horror fiction's "brand name" writers with the publication of his first novel, The Piercing, in 1979. He followed this with a number of other horror novels, including bestsellers such as The Legacy and Hobgoblin, before cutting back on genre writing in the mid-1980s. His short stories have been collected in a number of "best of" anthologies, including Modern Masters of Horror and The Year's Best Fantasy and Horror.
The Caddie Who Knew Ben Hogan, was published in 2006 and is a literary exploration of golf and everyday life. Norman Rush praised the novel, saying, "John Coyne has managed to employ golf as a lens through which aspects of Midwestern daily life in the 1940s, of thwarted love, of social class, are revealed with stark and unsettling clarity."
Coyne is the author of two other golf novels: The Caddie Who Played With Hickory, which is set in 1946 at the Midlothian Country Club, and The Caddie Who Won the Masters, set at Augusta National. His most recent novel is Long Ago and Far Away, a love story spanning forty years.