He worked with several rock and rollgroups during the early 1960s, most notably Rickie Shaw and the Dolphins, where he worked with future Hollies Tony Hicks and Bobby Elliott. Originally a pianist, Calvert, on Hicks's suggestion, switched to bass.
After the break-up of the Dolphins, Calvert played in a number of semi-professional outfits. However, unable to advance his musical career, Calvert took a factory job until he was asked to substitute for Hollies' then bassist, Eric Haydock, in a tour of Scandinavia. After the tour, Calvert played on an Everly Brothers album, and on the Hollies' single, "Bus Stop", before returning to his factory job. Shortly after that, he was invited to join the Hollies permanently in 1966.
In 1969, Calvert was invited to play bass on a still-unreleased album with the Bread and Beer band, which included Caleb Quaye, Roger Pope, Elton John and two Jamaican percussionists, Lennox & Rolfo.
Calvert left The Hollies in 1981, and is now playing with a Catholic church music group in Clitheroe, Lancashire. He still performs at local venues for charity, playing classic songs from the Hollies' era. Recently, he has been joined on stage by his son Mark, playing lead guitar.
Calvert is currently busy writing and recording new material, with his friend and well known local musician, John Maycraft.
On 24 September 2009 the Hollies were nominated for induction to the Rock and Roll Hall of Fame, and on 18 December 2009 were announced as inductees, to be inducted on 15 March 2010. They were represented at the RRHOF ceremony by Clarke, Nash, Sylvester, Eric Haydock and Calvert.