Gardiner was educated at Craigmount School in the Borders of Scotland and later Eastwood School, Glasgow. He joined his first school band the Vostoks in 1962. Next there were the Kingbees and the System where he joined musicians who would form Beggars Opera with him in 1969.
He has played in his own outfit, Beggars Opera, and also with David Bowie and Iggy Pop. For Bowie he played lead guitar on the 1977 album Low. He worked with Pop on Lust for Life the same year. The album included "The Passenger", regarded as one of Pop's best songs, for which Gardiner composed the music. Bowie biographer David Buckley described it as being "possessed with one of the greatest riffs of all time".
- Goldring, Susie (2007-04-18). "David Bowie - Low". Classic Pop/Rock Review. BBC. Retrieved 2009-01-05.
- Carr, Roy; Murray, Charles Shaar (1981). Bowie: An Illustrated Record. New York / London: Avon / Eel Pie Publishing. p. 118. ISBN 0-380-77966-8. OCLC 7862636.
- Buckley, David (1999). Strange fascination: David Bowie: the definitive story. London: Virgin Books. p. 318. ISBN 978-1-85227-784-0. OCLC 43757665.