An All-America quarterback for the Auburn Tigers, he won the Heisman Trophy in 1971 and then played six seasons in the National Football League (NFL) with the Atlanta Falcons and Washington Redskins.
Although a talented baseball and basketball player, he chose to play football for Auburn University where he would become the starting quarterback in 1969 under the tutelage of head coach Ralph Jordan.
[5][6][7] Sullivan left football to enter private business in Birmingham, where he worked in insurance and as a tire company executive.
During his time as an assistant Auburn won, or shared, three Southeastern Conference championships and had a four-game winning streak against archrival Alabama.
After two losing seasons, he led TCU to a 7–5 mark in 1994 to win a share of the Southwest Conference championship, the school's first SWC title since 1959.
Following the 1994 season, prior to the Horned Frogs' appearance in the Independence Bowl versus Virginia, Sullivan agreed to become the head coach at Louisiana State University (LSU).
However, LSU refused to pay the $400,000 buyout of Sullivan's TCU contract, and the Tigers hired Vanderbilt University coach Gerry DiNardo three days later.
He helped develop Darrell Hackney into the best quarterback in UAB history who was able to make it to the NFL as an undrafted free agent picked up by the Cleveland Browns.
After neck surgery in September 2003, Sullivan was diagnosed with throat cancer by Dr. William R. Carroll (squamous cell carcinoma) and began chemotherapy and radiation treatments in December.
On January 1, 2020, Auburn players wore "7" decals on the left side of their helmets during the Outback Bowl to commemorate Sullivan.
[8] Sullivan is one of at least 345 NFL players to be diagnosed after death with chronic traumatic encephalopathy (CTE),[9] which is caused by repeated hits to the head.