Cavanagh was a lock and second-rower, originally from Clifton. He had several seasons in Brisbane playing for Brothers, from where he gained selection on Australia's 1965 tour of New Zealand. In 1967, Cavanagh won a premiership with Brothers, kicking all of his team's points in a try-less 6–2 grand final win over Northern Suburbs.[2]
From 1968 to 1972, Cavanagh played his rugby league for North Sydney. He had a difficult start, breaking a hand in his first pre-season, then getting suspended for a stiff-arm tackle on his first-grade debut, but became an important player. At the end of the 1969 season, Cavanagh had a stint in England with Bradford Northern, playing under Gus Risman. He captained North Sydney during the 1971 season.[3]
Cavanagh was appointed captain-coach of Bundaberg in 1973.[4] He continued to live in Bundaberg after retiring and it was on his recommendation that North Sydney recruited local product Les Kiss. In 2008, Cavanagh was named as a lock in the Bundaberg Rugby League Team of the Century.[5]