Born in the Rollington Town area of Kingston, Jamaica, Gardiner attended Franklin Town Government School and St Monica's College, dropping out of education after being diagnosed with tachycardia.
In 1960 he joined Richard Ace's band the Rhythm Aces, which also included Delano Stewart, later of the Gaylads. With the group he recorded "Angella", and the local hit "A Thousand Teardrops". The group split up and by 1963 Gardiner had joined Kes Chin and The Souvenirs as vocalist, and began learning guitar. He went on to join Carlos Malcolm & the Afro Caribs with whom he started playing bass guitar after the original bassist left, and when that band ended he started his own group, the Broncos, named after the Bronco Club where they had a residency. He later played with Byron Lee's Dragonaires.In the late 1960s and 1970s he worked extensively as a session musician as a member of the Now Generation, The Upsetters, The Aggrovators, and The Crystallites. While working at Studio One he played on