Thomas John Bontly was the son of Thomas L. Bontly (1906-1968), a hotel cashier, and his wife, Mary Helen, née Hackett (1911-1971).
Bontly got his B.A. at the University of Wisconsin-Madison in 1961, and in the following year he was a Rotary International Scholar at Corpus Christi College in Cambridge, England. Bontly married Marilyn Mackie in 1962. They had one son.
Bontly got his Ph.D. at Stanford University in 1966. His dissertation was on Henry James (about whom he also published essays), and he also held a Wallace Stegner Creative Writing Fellowship. His first novel was published in 1966. Also in 1966, he began teaching literature and creative writing at the University of Wisconsin-Milwaukee, where he held many positions until his retirement in 2001.
The third of his four published novels was Celestial Chess (New York: Harper & Row, 1979), his only work relative to the genre of the fantastic. It follows an American academic in 1962 who is a visiting scholar at an imaginary college at Cambridge University. David Fairchild is there to study a particular medieval manuscript, long neglected, but which has an unsavory reputation and which Fairchild learns is haunted. Bontly's novel has a second narrative track following the twelfth-century author of the manuscript, Geoffrey Gervaise, a rogue priest. Thus as a novel Celestial Chess straddles multiple sub-genres, historical, detective and supernatural, and it does so successfully while maintaining a high level of interest and suspense.
Bontly's other novels are The Competitor (1966), The Adventures of a Young Outlaw (1974), and The Giant's Shadow (1988). The first concerns a single day at a shoe-store. The second is a boy's coming of age novel set in the summer before high school. The Giant's Shadow is a thriller set in West Germany about an American poet, who had defected to the Soviet Union years earlier, attempting to return to the West. Bontly also contributed stories, essays and reviews to many magazines.