He joined the Borovansky Ballet in 1954, eventually becoming one of its leading dancers. He became a foundation member of The Australian Ballet in 1962 where he starred in major ballets until 1973.
In the 1970s he worked with Ballet Victoria both as a choreographer and as Associate Artistic Director. Garth was Artistic Director of West Australian Ballet from 1980-82, and taught extensively across Australia during the 1980s and 90s. Garth was an acclaimed guest artist with Sydney Dance Company, as well as starring in musical theatre productions during 1990s. As well as being an outstanding performer, Garth has created many important ballets for The Australian Ballet, West Australian Ballet, Ballet Victoria, Ballet Philippines, Royal New Zealand Ballet, the Queensland Ballet and Sydney Dance Company.