His league debut came on 16 August 1997 when he played as a second-half substitute for Sam Stockley in the 2–1 defeat at home to Exeter City.
Mustafa joined Rushden & Diamonds in June 2000 and was a regular in the Conference winning side the following season.
He remained a regular in the Football League side the following season, but was transfer-listed in November 2002 after losing his place.
However, in November 2004 Hornchurch were in serious financial trouble after the collapse of their main sponsor and placed their entire squad on the transfer list.
In the 2018–19 season, Mustafa made five league appearances for Benfleet whilst working at the club as a coach.