He managed Stafford Rangers for a brief spell, and then from 2000, he began coaching clubs and nations in Asia and Africa, including the Bangladesh national team, Fortune, Hurriya, Mpumalanga Black Aces, African Warriors, Bay Stars, Chippa United, Golden Arrows, CAPS United, and Township Rollers.
In the 2015–16 season, he led Township Rollers to the Botswana Premier League title and the final of the Mascom Top 8 Cup before he was appointed technical director at South African side Baroka in January 2017.
In July 2017, he joined the Zimbabwean Premier Soccer League team Harare City as technical director and was promoted to manager a year later.
Harrison was a trainee with Southampton,[3] before joining John McGrath's Fourth Division side Port Vale in February 1980.
Harrison took up the job as head coach of Bay Stars, in South Africa's third tier, the SAFA Second Division for the 2012–13 season.
[4] Harrison was appointed head coach of Chippa United in April 2013[5] but despite not losing a game, was unable to prevent the team from being relegated at the end of the 2012–13 season.
He led the Rollers to the league title in controversial circumstances 2015–16, as the Botswana Football Association deducted the club ten points for fielding an ineligible player before the ruling was overturned on appeal.
[17] On 8 January 2020, he was appointed as head coach of Zimbabwe Premier Soccer League rivals Highlanders on a two-year contract.
[22] He quit the club following a third place finish to the 2023 Super League of Malawi season, reportedly with the intention of returning to England.