Marks was born in Holborn, London. He left Bell Lane School at 14 and started in entertainment at the Windmill Theatre. He then served in the RAF as a Flight Sergeant in the Middle East where he arranged concerts for servicemen. He also worked as an auctioneer and engineer. He started in variety at the Kilburn Empire in 1946, and his stage appearances included The Sunshine Boys and Fiddler On The Roof. He was also involved in comedy work with Peter Sellers and Harry Secombe which later led to the formation (along with writer Spike Milligan) of The Goon Show, though Marks himself was not to become a member of that comedy group
Films included The Frightened City and Scream and Scream Again.
His Television show Alfred Marks Time ran for 6 years on ITV. He compered Sunday Night at the London Palladium and appeared in numerous other television programmes including Albert and Victoria, The Good Old Days, Blankety Blank, Maybury, The Marti Caine Show, The Two Ronnies, The Generation Game, Lovejoy, Parkinson and The All New Alexei Sayle Show.
He was married to the actress Paddie O'Neil.