Harrison first got the taste for volleyball from his older sister, Jessica, who represented Australia at the highest level from the age of 16. He played ‘mini volleyball’ throughout his years in primary school, and then represented Rostrevor College in the National Schools Cup competition in high school. After a number of years playing both beach volleyball and indoor volleyball, and representing Australia at the junior level in both disciplines including a 5th place in the Youth Beach Volleyball World Championships, he decided to specialise in indoor volleyball after receiving an AIS scholarship in 2008. In 2010/2011 he played for the Swedish professional club team, Linköping VC, and returned again for the 2011/2012 season where they were Swedish champions, and he won the MVP award for the Swedish league. Harrison was first selected as a part of the Australian National Team in 2011 and went on to qualify for and compete in the London 2012 Olympic Games. He then signed with Italian A1 club, Marmi Lanza Verona for the 2012/2013 season. After missing out on the 2013 season, he come back to play in 2014, and in 2015 he represented Australia in all the major competitions. In 2016 he missed out on the important Olympic Qualification Tournament, but he made his return to the Volleyroos for World League.

He played for Hurrikaani Loimaa (Finland) in the 2016/17 club season.