Choy was born in Vancouver in 1939. A Chinese Canadian, he spent his childhood in the city's Chinatown. Choy graduated from Gladstone Secondary School and went on to attend the University of British Columbia, where he studied creative writing.

Choy moved to Toronto in 1962, and taught at Humber College from 1967 to 2004. He continues to teach at the Humber School for Writers. He was president of Cahoots Theatre Company of Toronto from 1999 to 2002.

Choy is the author of the novel The Jade Peony (1995) which won the [Trillium Book Award]] and the City of Vancouver Book Award. In 2010, it was selected as one of five books for the CBC's annual Canada Reads competition.

His memoir Paper Shadows: A Chinatown Childhood (1999) won the Edna Staebler Award for Creative Non-Fiction and was nominated for a Governor General's Award.

Choy's latest novel, All That Matters, was published in 2004 and was nominated for the Scotiabank Giller Prize. In 2005, he was named a member of the Order of Canada.