[3][4][5][6] At the age of seventeen, he became a quadriplegic as a result of a 2004 diving accident when he jumped head first into a shallow river.

He spent time recovering and undergoing physical therapy at Kew's Royal Talbot Rehabilitation Centre.

[5] While Harrison was rehabilitating following his accident, he was visited by a member of the national wheelchair rugby team who encouraged him to try the sport.

[4] He then went on to play in an international match against the New Zealand national wheelchair rugby team that year at the Oceania Regional Championships.

[16] He was a member of the team that retained its gold medal at the 2016 Rio Paralympics after defeating the United States 59–58 in the final.

[19] At the 2020 Summer Paralympics, the Steelers finished fourth after being defeated by Japan 52–60 in the bronze medal game.

COVID travel restrictions led to Steelers not having a team training since March 2020 prior to Tokyo.