Sloan was the primary quarterback in his junior season in 1964 while Namath was injured. The 1964 team finished 10–1, won the Southeastern Conference title, and was named the consensus national champion. However, in the 1965 Orange Bowl versus Texas, Sloan was forced out of the game with injury. Namath came off the bench to win MVP honors despite Alabama losing, 21–17.
After college, Sloan was selected by the NFL's Atlanta Falcons in the 11th round of the 1966 NFL Draft. He played sparingly as a back-up over the course of two seasons. In his brief NFL career, he only appeared in eight games, and only one as a starter. During those eight games, he completed 10 of 31 passes, for no touchdowns and four interceptions.
In 1973, Sloan took his first job as a head coach of the Vanderbilt Commodores. In his first season, Vanderbilt finished at 5–6, including a 1–6 record in conference play. During his second season, however, Vanderbilt finished at 7–3–1 and qualified for a post-season bowl game. The team was placed in the Peach Bowl against the Texas Tech Red Raiders. The two teams played to a 6–6 tie in the game. It was Vanderbilt's first bowl game since 1955 and second in school history.
The Texas Tech University athletic department offered Sloan head football coaching position in January 1975. Though Sloan originally declined, he took the job on January 2, 1975. Texas Tech was believed to have offered him a $30,000 per year contract, as well as $11,000 from television show income. He took five of his assistant coaches with him to the Red Raiders program, including defensive coordinatorBill Parcells. In his three seasons with Texas Tech, Sloan compiled a 23–12 record.
In late 1977, Sloan took his third head coaching job with the Ole Miss Rebels football program. Sloan was head coach for five seasons at Ole Miss, winning 20 games, losing 34, and tying one. His best season came in 1978 when the Rebels finished at 5–6.
In December 1982, Sloan decided to leave Ole Miss to become the head football coach for the Duke Blue Devils football program. In his first season at Duke, Sloan led the Blue Devils to a 3–8 record, despite beginning the season 0–7. In his remaining three seasons, he compiled a 10–23 record before resigning. Steve Spurrier was named as his successor.