After retiring from athletics, he went on to work as a fitness coach for several football clubs, including Chelsea, Millwall, Milton Keynes Dons, West Bromwich Albion and Watford.

He represented England and won a bronze medal in the 200 metres event, at the 1990 Commonwealth Games in Auckland, New Zealand, in 20.26 (w).

Mafe is a member of the British team which set the world indoor record for the rarely contested 4 x 200 metres relay on 3 March 1991 in Glasgow.

In July 2008, Roberto Di Matteo was appointed as the new manager of the Milton Keynes Dons after Paul Ince left to become Blackburn Rovers boss, and Mafe was appointed fitness coach at MK Dons to work alongside Di Matteo and his assistant Eddie Newton.

On 6 February 2011, Mafe left West Bromwich Albion when Roberto Di Matteo was relieved of his duties at the club.