Sharp first played football for Livingstone School but became a referee via the Duke of Edinburgh's Award Scheme in order to fulfil the Service in the Community component of the course. He gained his apprenticeship through the Hertfordshire County League before gaining promotion onto the Southern Football League middle from where he was promoted to Panel Referee for two seasons before being promoted as an Assistant Referee to the Football League and, finally, the Premier League. He was selected to run the line at the 1999 FA Cup Final. Sharp currently referees on the national Contributory List of match referees.