John has worked as an actor in theatres nationwide. Parts he has played include Marc in Art, Neville in Neville's Island, Adam in Someone Who'll Watch Over Me, Malcolm in Bedroom Farce, Donald Duck in Blue Remembered Hills, Bob in Pack of Lies, DI Hallet in The Business of Murder, Jerry in Betrayal, Deeley in Old Times, Michael Starkwedder in The Unexpected Guest, Jeremy Warrender in Spider's Web, Danny in Night Must Fall, Fancourt Babberley in Charley's Aunt, Alfred Doolittle in Pygmalion, Scrub in The Beaux' Stratagem, and Bottom in A Midsummer's Night Dream. John played the title role in a nationwide tour of Sherlock Holmes – A Study in Fear!, Norman Barthlomew in Anthony Shaffer's comedy thriller Murderer, and Robert in Stage Struck at the Theatre Royal Nottingham.

John's roles in various Pomegranate Theatre Chesterfield Play Seasons included Andrew Wyke in Sleuth, and George in Two And Two Make Sex. While on tour, he appeared in the title role in Raffles – The Mystery of the Murdered Thief. Most recently, John appeared as the title character in The Mysterious Mr Love as part of the Theatre Royal Nottingham Colin McIntyre Classic Thriller Season.

On Radio 4, he played James Miller in The Archers.

John is a founder of Rumpus Theatre Company, for whom his directing credits include Duet For One, Quartet, Jumpers, and Alfie. Rumpus has also produced his own plays and adaptations including Sorry, I Love You..., The Black Veil, The Comedy of Terrors!, The Judge's House!, The Ripper Files!, The Signalman, and The Pit and The Pendulum. The latter two were both subsequently produced by Bill Kenwright at the Theatre Royal, Windsor. The Judge's House! was produced in Germany, and The Nightmare Room has been produced in Illinois and Milwaukee, USA.

For Bridge Theatre, John has written the plays Blood Relations (first seen at Sheringham Little Theatre), and The Haunted House (first seen at Norwich Playhouse). Sorry, I Love You... has been produced throughout England, and as far afield as Nairobi in Kenya, and The Comedy of Terrors! was included in the 2022 Utah summer Shakespeare Festival.