Harrison began his career with Darlington, and made 10 Conference Premier appearances in the 2011–12 season before joining Sunderland in October 2012 after a trial.
[4][5] Together with Sunderland team-mate Connor Oliver, Harrison joined Hartlepool United in March 2014 on loan for the remainder of the season.
[6] Harrison rejoined Hartlepool United for a second one-month loan spell on 22 August 2014,[7] later extended to three months.
[14] He signed a new deal in March 2017,[15] but struggled for form in the 2017–18 season,[citation needed] and was released from his contract in June 2018 to join Scottish Championship club Falkirk.
[16] Harrison joined National League North club Spennymoor Town on loan in January 2019, and signed permanently at the end of the season.