Allen played in Cleveland for one season, returning to the University of Kentucky in 1948 to serve as an assistant football coach under Bear Bryant. He stayed at Kentucky after Blanton Collier took over as head coach in 1954, working as the team's defensive coordinator. In 1962, Tom Landry hired him as a backfield coach on the NFL's Dallas Cowboys. He became the head of the Cowboys' research and development department in 1970 and was charged with scouting opponents. Allen won Super Bowl VI and Super Bowl XII with the Cowboys and remained with the team until retiring in 1983. He died of cancer in a Dallas hospital in 1988.
