During his hall of fame acceptance speech, Kelly singled out his high school coach, Louis E. DeVicaris, for getting him to college.

In football, he played quarterback and middle linebacker, and was a kicker, punter and kick returner as well.

In 1962, Kelly led Morgan State in rushing, scoring and punting, and the team won the CIAA (Central Intercollegiate Athletic Association) Championship.

In 1963, his senior year, Kelly was selected as the Most Valuable Player in the Orange Blossom Classic.

[11] Buddy Young, who was working for the NFL at the time, brought Kelly to the Browns' attention as a potential draft pick.

He was backup running back behind featured fullback Jim Brown and blocking halfback Ernie Green.

In game 12 of the 1970 season, he passed Bill Brown as the career rushing-yards leader among active players, a position he maintained until his retirement in 1974.

[24] After his retirement as an active player, he remained in the World Football League as the Philadelphia Bell's offensive backfield coach, joining two other Hall of Famers on that staff, former Green Bay Packers defensive backfield standouts Willie Wood (the first black head coach in pro football history) and fellow Philadelphian Herb Adderley (defensive coordinator).

[3][29] Felicia Kelly, Leroy's only daughter, worked in the local news business for 20 years at Cleveland's ABC affiliate WEWS-TV.

She worked in the engineering department, as a news source reporter, and hosted a half-hour entertainment show called "The Set."

David Kelly, his eldest son, is sports anchor and reporter for KMSB-TV in Tucson, Arizona.

Leroy Kelly II was invited to 2 workouts with the Cleveland Browns and 1 with the Detroit Lions.