Harrison is a product of the Tranmere Rovers youth system, having joined the side as a 13 year old, he made his first team debut in 2001 at home against Wigan Athletic. He went on to make 125 appearances for Tranmere before joining Rotherham United in 2007 where he made an additional 188 Football League appearances. In June 2012, it was announced that Harrison had rejoined Tranmere and the following summer he joined Chester FC.
Harrison joined The Nomads in January 2015 and made his debut in a 1-0 victory over Bala Town. Harrison has gone on to be a regular fixture in the side, including playing in the club's three Europa League campaigns.
|Competition||Appearances||Goals||Assists||Yellow Cards||Red Cards|
|Welsh Premier League||113 (4)||1||0||28||2|
|FAW Welsh Cup||17 (1)||0||0||2||0|
|Welsh League Cup||4 (1)||0||0||0||0|
|UEFA Europa League||7 (0)||0||0||1||0|
|Europa League Playoff||2 (0)||0||0||1||1|
|Scottish Challenge Cup||6 (0)||0||0||0||0|