After college, Sullivan had a six-season professional NFL football career. He was a second-round selection (40th overall pick) of the 1972 NFL Draft by the Atlanta Falcons. Sullivan played with the Falcons from 1972 to 1975. He played in 30 games. In 1974, Sullivan started three games for the Atlanta Falcons, losing all three. He completed 48 of 105 passes and one touchdown. In 1975, he threw for 3 touchdowns, completing 28 of 70 passes. He signed with the Washington Redskins as a free agent in 1976 but was cut before the start of the season. He signed with the Chicago Bears in March 1977 but was sold to the San Francisco 49ers in June, and then cut by the 49ers before the start of the 1977 season. Sullivan left football to enter private business in Birmingham, where he worked in insurance and as a tire company executive.
