John Forbes was born in Melbourne, Australia, but during his childhood his family lived in northern Queensland, Malaya and New Guinea. He went to Sydney University and his circle of friends included the poets Robert Adamson, Martin Johnston, and John Tranter. It was at this time that the work of the American poets Ted Berrigan, John Ashbery and Frank O'Hara made a strong and lasting impression on him.
He returned to live in Melbourne in the late 1980s, where he became the poetry editor of Scripsi. His friends around this time included the poets Gig Ryan, Laurie Duggan and Alan Wearne.
Forbes died in Melbourne of a heart attack, aged 47.