Born in Manchester, Gannon had played in bands with friends since he was 12 years old, and in 1983 joined Aztec Camera after replying to an ad in Melody Maker.
[2][3] After another brief stint in The Colourfield, when bass player Andy Rourke was fired from the Smiths in early 1986, Gannon was hired to replace him.
Within a fortnight, however, Rourke was reinstated and Gannon moved to rhythm guitar, becoming the official fifth member, playing on the "Panic" and "Ask" singles and touring the UK, Canada, and the US with the band.
[7] He has played guitar with many other artists, including Terry Hall, Roddy Frame, Alison Moyet, Denise Van Outen, Edwyn Collins, and Paul Quinn.
He was also asked to join Orange Juice's James Kirk and Steven Daly's band Memphis), Buzzcocks/FOC, Robert Lloyd, Deadly Avenger, Red Venom, Vinny Peculiar, and The Family Foundation.