Hibberd studied medicine at the University of Melbourne, where he resided at Newman College and practised as a clinical immunologist in Melbourne from 1964 until 1973. He is married to the actress Evelyn Krape, and a father to Lily (1972) and James (1984) from a first marriage, and Spike and Molly.
Hibberd co-founded The Australian Performing Group (APG); he was a member of the APG for ten years and chairman for two. In 1983 he founded the Melbourne Writers Theatre. In 2005, Hibberd was appointed until April 2008 to the Literature Board of the Australia Council for the Arts
His first play White With Wire Wheels was staged in 1967 at the University of Melbourne. Shortly afterwards, his short play Three Old Friends was the first production to be staged at the La Mama Theatre, opening on 29 July 1967 with a cast composed of Graeme Blundell, Bruce Knappet and David Kendall. Hibberd's most famous works are the plays Dimboola (1969) and A Stretch of the Imagination (1972). In 1973, David Williamson directed a sold-out season of Dimboola at the Pram Factory. In 1979, it was made into a film. A Stretch of the Imagination has been produced in the UK, USA, Germany and China (the Shanghai production in 1987 was the first performance of an Australian play in that country). His parody of an opera, Sin (1978) is inspired by Brecht/Weill's The Seven Deadly Sins.
La Mama Theatre re-mounted a forty year anniversary production of Three Old Friends along with Just Before the Honeymoon and This Great Gap of Time, opening 18 July 2007 and directed by Matt Scholten, along with two productions of A Stretch of the Imagination, one directed by Laurence Strangio (a radical re-interpretation featuring two performers) and another by Greg Carroll. In 2008, La Mama produced Dimboola again.
In 2009 a new production of A Stretch of the Imagination will be taken on a national 14-week tour to 26 venues by HIT Productions. Directed by Denis Moore, the play stars John Wood, best known for his TV roles, especially Sen. Sergeant Tom Croydon in Blue Heelers.
Jack Hibberd also regularly reviews plays and books for the media and practices medicine part-time.