2003 Clements made his debut in the
NASCAR Xfinity Series (then NASCAR Busch Series) in 2003 at
Pikes Peak International Raceway. Driving the No. 71
Chevrolet for
Young Racing, he started 35th and finished 31st after an early crash.
2007 Clements did not return to the
NASCAR Xfinity Series again until 2007, when Clements signed with
McGill Motorsports to run the last five races of the season in their No. 36
Chevrolet. He only finished two races and had a best finish of 23rd at
Charlotte Motor Speedway.
2008 In 2008, Clements attempted four races for his family-owned No. 50 team. He qualified for two of them, earning finishes of 22nd and 30th. During these two years, he also spent time practicing and qualifying cars for
Joe Gibbs Racing in races that conflicted with the
NASCAR Sprint Cup Series schedule.
2009 For 2009, Clements increased his focus on the
Xfinity Series, attempting thirteen races and making twelve. He ran six races in his family-owned No. 50 with a best finish of sixteenth. Shortly before the October race at
Kansas Speedway, Clements and sponsor Saxon Group joined forces with
JD Motorsports to finish out the season in the No. 0 Chevrolet. In his second race with JD, he finished a then-career best twelfth at
Auto Club Speedway.
2010 In the offseason, it was announced that Clements would drive at least the first three races of the 2010 season in the No. 0 for JD Motorsports with sponsorship from
Boudreaux's Butt Paste. After missing the field at
Daytona due to qualifying being rained out, his plans for the rest of the season were up in the air. The No. 0 team was shut down, and JD moved Clements to the No. 04. He attempted the next two races as planned, but failed to qualify for both of them. Clements made his first race of the season in April at
Nashville Superspeedway, finishing 22nd. He attempted nineteen more races, qualifying for fifteen of them. Clements earned his first career top-ten at
Gateway International Raceway in October, finishing tenth and also leading six laps (the first laps led of his career).
2011 In 2011, Clements competed in all 34 races, finishing fifteenth in points. He had no top-ten finishes, but had three fourteenth-place finishes and ten top-twenty finishes during the season.
2012 For 2012, Clements continued in the Xfinity Series with his team. He drove two races for
JD Motorsports at Richmond and Indianapolis when
Ty Dillon was using his 51. Clements had two top-ten finishes.
2013 After finishing 33rd in the first race of the
2013 NASCAR Nationwide Series season, Clements was suspended indefinitely by NASCAR on February 27, 2013. The sanctioning body stated that the suspension was due to violations of the NASCAR Code of Conduct, as defined in Section 7–5 of the sanctioning body's rulebook, as well as Section 12–1, actions detrimental to stock car racing. Clements, in an interview with ESPN, was later quoted as saying, "When you say 'racial' remark, it wasn't used to describe anybody or anything. So that's all I'm going to say to that. And it really wasn't. I was describing racing, and the word I used was incorrect and I shouldn't have said it. It shouldn't be used at all." The MTV editor who had the conversation with Clements,
Marty Beckerman, confirmed that Clements said a phrase that included the "n-word". Clements sat out two races and returned for the rest of the season. His season was highlighted by top-ten finishes at the huge
Talladega Superspeedway tri-oval and the series' inaugural race at the
Mid-Ohio Sports Car Course. At the
Gardner Denver 200 at
Road America, Clements recorded a then career-best sixth place finish.
2015 2015 was a decent season for Clements despite a best finish of tenth at Dover and a handful of poor finishes.
2016 At Talladega in 2016, Clements led laps under caution and recorded his first Xfinity top-five finish, a fourth.
2017 . In 2017, Clements scored a top-ten outing at Iowa, in which he finished seventh. A few races later, he would score his first career win at Road America after he and
Matt Tifft got together with two laps to go. Clements' win was the first for an independent Xfinity Series driver and team not affiliated with NASCAR's Cup Series since
David Gilliland won at
Kentucky in 2006.
2018 In 2018, Clements would finish inside the top twenty in 27 of 33 races, and finished fifteenth in the final standings.
2019 Clements showed similar consistency in 2019 and finished fourteenth in the standings.
2021 The 2021 season would be one of Clements' best. Despite not winning a race, he scored eight top-ten finishes and qualified for the playoffs on points. He finished twelfth in the final standings, tying his best points finish.
2022 In
2022, Clements scored his second career win after a firm tenth-place finish at Watkins Glen put him in a good starting place at Daytona. The win at the
Daytona night race after overtime, earned him a playoff appearance at first. However, NASCAR issued the team an L2 penalty four days later after the post-race inspection discovered an illegally modified intake manifold. Clements kept the win but was declared ineligible for the playoffs. In addition, crew chief Mark Setzer was fined 60,000, and the team was docked 75 owner and driver points, plus 10 playoff points should the team qualify for the postseason. Clements' appeal was heard on September 13; panel members Tom DeLoach, Richard Gore and Dixon Johnston found in Clements's favor, rescinding the penalty and revoking the punishments. As a result, he regained his eligibility for the 2022 playoffs. Clements finished twelfth in the points standings.
2023 2023 was a disappointing season for Clements. He recorded seven top-fifteens, with his best showings being two fourteenth place finishes. He failed to record a single top-ten finish and finished nineteenth in the point standings.
2024 Clements' 2024 season would follow a similar trend to the previous season. He scored just one top-ten finish, a sixth-place finish at
Atlanta, and finished twentieth in the standings.
2025 in 2025 Clements began the
2025 season with a ninth-place finish at
Daytona. Clements was awarded an extra point because he scored the Xfinity Fastest Lap in the race. At
Circuit of the Americas, Clements made his 500th Xfinity Series start, becoming the fourth driver to do so. He ended the season with four top-ten finishes and finished 21st in the standings. ==Motorsports career results==