A native of Athens, Tennessee, Grubb attended the University of Tennessee, where played college football as a Guard and tackle for the Tennessee Volunteers under head coach Bowden Wyatt from 1958 to 1960.[3] He was named to the Southeastern Conference's All-Sophomore team in 1958 and earned scholastic All-American honors as a senior in 1960.[4] Grubb began his coaching career at Cordova High School in Cordova, Alabama, serving as head coach for five seasons, from 1961 to 1965, and leading his teams to combined record of 38–8–4. He spent three seasons, from 1966 to 1968, as the line coach as Samford under John Lee Armstrong, before succeeding Armstrong as head coach in 1969.[5][6]