Johnson was born in 1948 in Evanston, Illinois. He first came to prominence in the 1960s as a political cartoonist, at which time he was also involved in radical politics. In 1970, he published a collection of cartoons, and this led to a television series about cartooning on PBS. Johnson's first novel,
Faith and the Good Thing was published in 1974. In 1990, he was awarded the National Book Award for
Middle Passage.
Johnson received his B.S. and M.A. from Southern Illinois University in 1971 and 1973, respectively; he got his Ph.D. in philosophy from SUNY-Stony Brook in 1988. In 1976, Johnson was hired to teach at the University of Washington in Seattle, Washington.
In 1977, Johnson became a Buddhist.
Johnson's mentor, early in his writing career, was the writer John Gardner. In an interview, Johnson wrote, of Gardner:
"Gardner, as I’ve said often, was the hardest-working writer I’ve ever known in my life. “Writing is the only religion I have,” he once said, and this was true. He was prolific, innovative, learned (a scholar of medieval literature ), radically independent, a translator who said he knew twelve languages, a poet, librettist, novelist, short story writer, a composer of scripts for radio and films, a critic and literary scholar, player of the French horn: a true cornucopia of creativity. He could write for 72-hour stretches without sleep. But, no, he was not a gifted storyteller, as he would have admitted. His most enduring novel is Grendel, which is, of course, derived from the story we receive from the Beowulf poet. But he was an American philosophical writer, like Saul Bellow."
Recently retired,, Johnson was the S. Wilson and Grace M. Pollock Endowed Professor of English at the University of Washington and is a MacArthur Fellow. He is also the recipient of a Guggenheim Fellowship. In 2003 he published
Turning the Wheel, a collections of essays about his experiences as an African-American Buddhist.