He was the 14th head football coach for the Howard Payne University in Brownwood, Texas, serving for three seasons, from 1979 to 1981, and compiling a record of 6–23–1.
[2] Mayo moved to the college ranks in 1968 when was hired as the head coach of the freshman football team at Rice University in Houston.
[3] From 1972 to 1977, Mayo was the offensive coordinator at Howard Payne University in Brownwood, Texas, coaching under Dean Slayton.
As offensive coordinator, Mayo helped guide the Angelo State Rams to a NAIA Division I Football National Championship.
In December 1978, Mayo was hired as head football coach and athletic director at Howard Payne, succeeding Slayton.