The Aucklander was selected in the coxed four for the 1980 Moscow Olympics, but never competed because of the American-led boycott that year. However, at Los Angeles in 1984 he won an Olympic bronze medal in the coxed four and at Edinburgh in 1986 he won a Commonwealth Games silver medal with Ian Wright in the coxless pairs. Mabbott also picked up a bronze medal with the New Zealand eight in Edinburgh. He was a member of the New Zealand eight that won the world title at Duisburg in 1983.
Rowing for the North Shore club, the methodical and organised Mabbott won national titles in the coxed four in 1982 and 83.
For some years, Mabbott has been the high performance commissioner for New Zealand Rowing. Previously he was involved with Learn to Row programmes with the North Shore club.
Mabbott, married to Gillian, was formerly a partner in a crane and construction hire business.