Johnnie Mack returned to Lakeland and joined the Southeastern coaching staff before the 2020 season with a long list of playing and coaching experience on offense, special teams, and strength and conditioning and has recruited the football hotbeds of Florida, Texas, California, and Oklahoma. 

Prior to SEU, Mack was at Hawai'i where he was over offensive quality control and wide receivers. Mack mentored a pair of All-Mountain West receivers in Cedric Byrd and Jojo Ward. Byrd, Ward, and Jared Smart became the first trip of receivers to each have 1,000-yard receiving season in program history. The Warriors were the West Division Champions and won the Hawai'i Bowl, and reached the 10-win mark for just the sixth time in program history. Hawai'i was also in the Top 10 in passing offense, and Top 15 in total offense. 

Mack also spent a season at NCAA Division I FCS Houston Baptist as the Offensive Quality Control Coordinator and Running Backs Coach, helping the Huskies average nearly 400 yards per game. He also coached inside receivers and return specialists at North Texas for a season, helping the Mean Green win the Conference USA West Division title and appeared in the New Orleans Bowl. 

The Polk County native also worked as a graduate assistant at East Central University, and was a strength and conditioning assistant at Southern Methodist. 

Mack played for Mike Leach at Texas Tech as a running back and kick returner where he set a program record for single game kick return average at 60. He finished third in the Big XII in 2003 and 27th nationally in kick return average (24.8)and finished third on the Red Raiders single-season kickoff return yardage list at 546. He also played for Bill Castle at Lakeland High School, helping the Dreadnaughts win a state title in 1999.