His first band The Blades he founded in 1963 with Ian Anderson. The band was called from 1965 to 1966 John Evans band. Other members were Jeffrey Hammond and Barrie Barlow. A year later became of them John Evans Smash, with Jeffrey Hammond of Glenn Cornick was replaced. During this time, Evans shortened his name to Evan. 1968 saw the establishment of Jethro Tull without John Evan. It was not until 1970, when the recording of the third Jethro Tull album Benefit, a member of the band. On the cover Evan is not mapped as a group member. However, he is on some titles ( Alive and Well on Living in, Son, Play in Time, Sossity; You're a Woman and Teacher ) to hear the piano and organ.
Overall, John Evan worked on twelve Jethro Tull albums. After 1980, the album Stormwatch was published, Evan and David Palmer parted from Jethro Tull. They founded the band Tallis, but was commercially unsuccessful. Later John Evan was a fairly successful building contractor.