An accomplished 9-time AMA National Amateur Champion, the Duke turned pro in 2005 where he took third place in the Supercross 125 East Series and won the East/West shootout with teammate Andrew Short. He made even more of a splash in 2006, exploding onto the national scene and winning the AMA Supercross Lites East Championship aboard a Honda CRF250R. No sooner had the last gate of the Supercross season dropped than Millsaps jumped up to the 450 class, riding in the AMA Motocross Championship on a CRF450R, consequently shocking the veterans by taking third overall.
But then lady luck showed just how fickle she can be. In 2007 Millsaps broke his femur just before the start of the Supercross season.
In 2008 Millsaps was back: healthy, ready and raring to win. And win he did, with two Supercross victories and eight podium finishes. Then, just into the outdoor nationals, Millsaps was injured again, this time with a separated shoulder.
Cut to 2009: Millsaps had a good Supercross season, finishing eighth overall but standing on the podium four times. Then at Hangtown early in the Motocross season, Millsaps was once again injured, this time hurting his neck and taking him out for much of the season.
2010 saw Davi capture a win at the 450 Supercross race in San Diego and finish 3rd overall in the standings.
In two subsequent seasons with the JGR team, Millsaps finished 10th (2011) and 9th (2012) in Lucas Oil Pro Motocross 450 Class points.
Davi Millsaps made the move to the Rockstar Suzuki squad for 2013, the team's first season fielding a 450 rider. With all the questions surrounding the team's ability to be competitive, Millsaps entered the Supercross season way under the radar, but emerged from the opening round at Anaheim victorious. After grabbing the holeshot in the Main Event, Millsaps held the lead until Canard passed him with 4 laps to go. Millsaps held tight though and passed him back on the race's final lap to complete the stunner.