Gary was born on 29 May 1949 in East Ham. In 1962, he formed the Paramounts with his friend Robin Tower. The Paramounts performed several times on the same bill as the Rolling Stones in the early 1960s but split up and reformed in 1967 as Procol Harum. Gary was the unmistakable voice on their first single "A Whiter Shade Of Pale," which scored them a monster hit both sides of the Atlantic, and everywhere else in between.
The band's line-up consisted of Robin Trower on guitar, Matthew Fisher on mellotron and keyboards, David Knight on bass and B. J. Wilson on drums. They split up in the mid-1970s, and Gary joined Eric Clapton's band. Procol Harum reunited and recorded a new album in the late 1990s. In 1997 Gary toured with Ringo Starr's All Starr Band.