After serving in the Air Force, Johnson attended the University of Michigan in the mid-1970s where he began broadcasting on the University radio station and then on Ann Arbor station WAAM (at the time a popular Top 40 station). In 1977, he began broadcasting on WGPR (107.5) in Detroit and soon gathered a diverse audience attracted to his "genre bending" format. Moving to WJLB around 1982, Mojo gained additional listeners at the more easily found 97.9 frequency and billboards throughout Detroit touted the "Landing of the Mothership" at 10:00 every night.