Career

Having played for AFC Wimbledon since age ten, Harrison made his debut for AFC Wimbledon on 2 September 2014, coming on for Callum Kennedy at half-time during a Football League Trophy victory over Southend United at Kingsmeadow. He made his Football league debut on 13 September 2014, playing the full game at Accrington Stanley which ended in a 1–0 defeat for the "Dons". Harrison signed his first professional contract with AFC Wimbledon on 26 September 2014.