Shirley began playing drums at an early age (Apostolic Intervention) and was recruited by vocalist and guitarist Steve Marriott to join the newly formed Humble Pie when he was just 17 years old. Shirley remained as Humble Pie's drummer throughout the group's entire career. He also worked on Steve Marriott's solo projects, and was a co-founder of the popular 1980s group Fastway. Shirley co-wrote Fastway's biggest hit, "Say What You Will".
Shirley returned to the UK in 1999. In 2000 he reformed Humble Pie with their original bassist Greg Ridley and another former band member, guitarist and vocalist Bobby Tench. He also appeared in a memorial concert for former Humble Pie bandmate Steve Marriott. More recently he has performed with the Deborah Bonham Band.