At Auburn University, Gaines became a five-time NCAA champion. During one four-year period, Gaines held eleven world records and, had the United States not boycotted the 1980 Moscow Olympics, he would have been a favorite to win multiple medals. After graduating from Auburn in 1981, he stopped swimming for several months, thinking he had missed his opportunity to be an Olympic medalist, but was urged to resume swimming by his father. When Gaines qualified at the 1984 Olympic trials, his times were not particularly impressive and he was not expected to place at the 1984 Summer Olympics in Los Angeles, California. He won the 100 meter freestyle off a very good start and swam the anchor leg for both the US gold medal-winning 4 × 100-meter freestyle and 4 × 100-meter medley teams.
In August 1991, Gaines was temporarily paralyzed with Guillain-Barré syndrome. After a two-month hospitalization, he experienced a surprising full recovery attributed largely to his superb physical condition as a competitive swimmer. He eventually regained world-class times and, at the age of 35, became the oldest swimmer to qualify for the trials for the 1996 Summer Olympics. Ultimately, he chose not to compete in the trials for Atlanta but rather continue his career as a television commentator, covering swimming for NBC at the Games.
Gaines was Outreach Director for the Alabama Sports Hall of Fame in Birmingham, Alabama from 1997 until 2003 when he moved to Colorado Springs, Colorado to become the Chief Fund-raising and Alumni Officer for USA Swimming. In December 2007, Gaines became a spokesperson for LIMU, The Company, a Direct Sales Company that manufactures LIMU ORIGINAL, BLU FROG, LIMU LEAN, and LIMU ORIGINAL SHOTS.
Gaines currently resides in Lake Mary, Florida where he is Executive Director of Rowdy's Kidz, a charitable program sponsored by LIMU, The Company. His wife, Judy, and he have four daughters: Emily, Madison, Savanna and Isabelle.
- International Swimming Hall of Fame
- U.S. Olympic Hall of Fame
- Alabama Sports Hall of Fame
- Florida Sports Hall of Fame
- 1982 McDonalds Spirit Award
- 2007 NCAA Silver Anniversary Award