In late 1964, he and Peter Eden came across Donovan in Southend, Essex, and offered to manage him. They produced Donovan's first hit single and debut album, What's Bin Did and What's Bin Hid.
In 2005, Stephens worked with Peter Callander and David Cosgrove on the musical production of Bonnie & Clyde.
He also formed The New Vaudeville Band, and their song "Winchester Cathedral" won Stephens the 1967 Grammy Award for Best Contemporary (R&R) Recording.
He wrote a long series of hit records, often in conjunction with other British songwriters including Tony Macaulay, John Carter, Roger Greenaway, Peter Callander, Barry Mason, Ken Howard, Alan Blaikley, Don Black, Mitch Murray, and Les Reed.
Stephens was an English songwriter and record producer, most prolific in the United Kingdom in the 1960s and 1970s.