[4][5] Smart began his playing career at Bainbridge High School and went on to play college football at the University of Georgia, where he was teammates with defensive linemen Antonio Cochran, Emarlos Leroy, linebacker Brandon Tolbert, Pro Football Hall of Fame cornerback Champ Bailey, and Super Bowl MVP Hines Ward.

[6] Smart was a four-year letterman at defensive back for Georgia and a first-team All-SEC selection as a senior.

[15] From 2002 to 2003, Smart worked as a graduate assistant under Bobby Bowden at Florida State while pursuing a master's degree.

[17] Smart rejoined the Georgia Bulldogs football program to serve as running backs coach for the 2005 season.

[24] Smart considered a lucrative contract to be the defensive coordinator at his alma mater, the University of Georgia but chose to stay with the Crimson Tide in early January 2010.

[26] On March 27, 2012, the University of Alabama System's Board Of Trustees voted to increase Smart's salary and extend his contract.

[29] On April 16, 2013, Smart was granted a $200,000 salary increase to make him the highest-paid defensive coordinator in college football.

[32] Smart has had 6 of his assistant coaches become head coaches at the FBS level: Shane Beamer for South Carolina, Sam Pittman for Arkansas, Mel Tucker for Colorado and Michigan State, Dan Lanning for Oregon, Fran Brown for Syracuse, and Dell McGee for Georgia State.

[36] Smart's first year as Georgia's head coach ended with a 31–23 victory over TCU in the Liberty Bowl.

[37] In the 2017 season, Smart led the Bulldogs to their first 9–0 start since 1982 and won the SEC East after a victory over the South Carolina Gamecocks on November 4.

[38][39] On December 2, 2017, Smart coached Georgia to its first SEC title since 2005, and only the fourth 12-win season in school history (1980, 2002, 2012).

[44] The Bulldogs went on to lose to Alabama in the National Championship Game 26–23, where Alabama freshman quarterback Tua Tagovailoa relieved Jalen Hurts late in the contest and ended the game on a 41-yard touchdown completion to DeVonta Smith in overtime.

[45] Smart was named SEC Coach of the Year for the 2017 season and received the George Munger Award.

[47] Georgia earned a spot in the SEC Championship game as the Eastern Division Champions, but lost to Alabama, 35–28.

[69] With this victory, Smart became the first of Saban's former assistants at Alabama and just the second overall to defeat Saban (Jimbo Fisher, a former assistant at LSU and the head coach at Texas A&M, was the first after his unranked Aggies team upset the Crimson Tide earlier in the season).

[71] In July 2022, Smart and Georgia agreed to a 10-year contract extension worth $112.5 million, making him the highest-paid coach in college football.

[83] Smart additionally led the Bulldogs to an SEC-record 29-game win-streak with a 31–23 win over in-state rival Georgia Tech in Week 12 of the regular season, finishing it 12–0.

[85] As a result of the loss, Georgia was not among the top four ranked teams that made the College Football Playoff, and instead played Florida State in the Orange Bowl.

[86] In May 2024, Smart and Georgia agreed to a ten-year contract extension worth $130 million, once again making him the highest-paid coach in college football history.

[89] In a rematch against Texas, he led the Bulldogs to a conference title with a 22–19 overtime win,[90] clinching the #2-seed and a first-round bye for the College Football Playoff.

[92] Smart is married to Mary "Beth" Elizabeth Lycett, who played basketball for the University of Georgia.