Mack attended Fort Pierce Westwood High School in Fort Pierce. He had played quarterback and was nicknamed "Bombshell Man. " However, throwing the ball short was a major struggle for Mack so he became a linebacker. The rest of his athletic career he had been relying on basketball to get him a college scholarship but his plans were dashed by a tear in his patella tendon before his sophomore season. After this injury, his high school football coach, Waides Ashmon, recruited him to the sport, promising Mack and his parents that it would earn him a scholarship.