Born Robert Wass, Knutt began performing whilst still at school in the early '60s as a singer in a a number groups. He later moved into comedy, performing on the working mens' club circuit with partner Geoff Morton as double act Pee and Knutt, before going solo in the mid '60s and securing slots on The Comedians and The Wheeltappers and Shunters Social Club.
In 1977, Knutt was cast in the lead role for Ken Loach's two part Play for Today drama, The Price of Coal which looked at life for a Yorkshire mining community. Other acting roles included parts in Coronation Street, Last of the Summer Wine, Hetty Wainthrop Investigates, Our Friends In The North, Common as Muck, All Creatures Great and Small, Heartbeat and a recurring role in Emmerdale as Zak Dingle's brother, Albert. In 2012 Knutt announced his retirement from panto and cruise liner cabaret work due to a shoulder operation that went wrong. Most recently, he had been starring in the long running ITV sitcom Benidorm.
In 1986, Knutt married Olympic Bronze 4x400 relay medallist and one time award winning body builder Donna Hartley and remained with her until her death in 2013 at the age of 58.