Shearston played guitar and sang English, American and Australian folk songs. At 19 he become a full time singer. He worked in hotels and sang at "The Folksinger". He sang with the American gospel and blues singer Brother John Sellers. In 1962 Shearston signed a recording contract with "Leedon". The next year Leedon's distributor, "Festival", signed him to CBS. In March 1965 Sydney radio stations started playing a song from his record, "Australian Broadside". His song "Sydney Town" hit the Top 10 in his home city. In 1966 and 1967, Shearston was Australia's biggest selling folk singer. He had his own national television show, "Just Folk". Peter, Paul and Mary recorded a song he wrote called "Sometime Lovin". They invited Gary to go to America. He spent a year in London and then 4 years on the East Coast of the United States of America. In 1972 he went back to England and recorded some songs for the album "Dingo". He had big hit with his deadpan (flat, no emotion) version of Cole Porter's "I Get A Kick Out Of You". In 1990 he received the Tamworth Songwriters' Association's prize for "Bush Ballad of the Year".