He played in the Football League for Birmingham City, Portsmouth, Newcastle United and Reading, and was capped once for England under-21.

Under the guidance of the management duo, Reading were promoted to Division One after finishing as runners-up to Brighton & Hove Albion in the 2001–02 season.

Pardew resigned in September 2003 and Dillon stepped in as the caretaker manager, until Steve Coppell was appointed in October 2003.

Dillon passed his UEFA Pro Licence in 2004 and in the 2005–06 season Reading won the Championship with a record of 106 points.

He brought in no fewer than ten new faces, including arguably the most eye catching deal of the summer in League Two when he completed the signing of Glen Little from Sheffield United.

But on 10 January 2011, after a run of just two wins in the previous ten League games and with attendances declining, Dillon and assistant Gary Owers left the club by mutual agreement.