John Bennett was educated at Bradfield College in Berkshire, then trained at the Central School of Speech and Drama, followed by a wide repertory theatre experience including Bromley, Bristol Old Vic, Dundee, the Edinburgh Festival and Watford before going to London's West End.

Often cast as a villain, Bennett had many roles on television including Market in Honey Lane, Porridge, Survivors, The Avengers, Strange Report, Bergerac, The Professionals and four episodes of The Saint. He also appeared in several films including The Fifth Element and The Pianist. He also had an extensive stage career.