Kelly played for Leyton Orient and Darlington in the Football League and had later spells with clubs in the Scottish League, before finishing his career with in the Irish League. Kelly began his career with Chelsea but did not make a first team appearance. He had a two-month loan spell in March 1996 with Third Division side Leyton Orient before joining Darlington in August, then also of the Third Division.
He then moved to Scottish football, signing for Street Mirren in August 1997.
After a season there, he dropped a division to sign for Ayr United after a short spell in Iceland. He left Ayr for a short spell with Partick Thistle in March 2000.
Kelly then joined in November 2000, where the fans funded his signing. He made a great start to his Blues career, scoring in December against arch-rivals Glentoran.
He also played for in Union of European Football Associations Champions League qualifying against Football Club Torpedo Kutaisi.
Kelly was released by in May 2003.