After an ill-fated singing career in the 1960s, Johns began working as a recording studio engineer. In 1969, Johns was called upon to rescue the near disastrous Get Back sessions for The Beatles. Johns compiled several versions of the album, which were all rejected by the band, before the project was eventually turned over to producer Phil Spector. Spector then crafted the released album, which was retitled Let It Be.
His work on the first three albums by country-rock group the Eagles, was fundamental in establishing the group's sound and style.