Gravel began racing in quarter midgets at age six with the Silver City Quarter Midget Club in Meriden, Connecticut. He accumulated more than fifty wins in that discipline, including national championship results, before progressing through micro-sprints. In 2007 he raced 600cc micro-sprints and finished third in points at Linda's Speedway in Pennsylvania, recording nine feature victories that year.
In 2008 Gravel climbed into a full-sized 360-sprint car for the first time, racing with the United Racing Club. He won twenty URC features that season and became the youngest feature winner in the series' more than sixty-year history. At the end of the year he was honoured as the 360-sprint car Rookie of the Year by the North American Sprint Car Poll.
After one URC season, Gravel moved up to a 410-sprint car with the UNOH All Star Circuit of Champions in 2009. He finished fifth in points in his debut season before improving to third in 2010, the same year he earned his first All Stars victory at Limaland Motorsports Park during Ohio Sprint Speedweek — a multi-race event of which he also claimed the overall title. He finished third in All Stars points again in both 2011 and 2012, continuing to accumulate victories and fast-time awards while making increasing incursions into World of Outlaws events.
Gravel made his first World of Outlaws Sprint Car Series start in October 2011 at Talladega Short Track, taking his maiden series victory on 22 October. He moved to the World of Outlaws full-time schedule in subsequent seasons and earned the series Rookie of the Year award in 2013. He drove for a succession of teams across the mid-2010s — Roth Motorsports in 2014, Destiny Motorsports in 2015, and CJB Motorsports from 2016 to 2018 — accumulating consistent race wins and top-five finishes but not yet breaking through to championship contention.
In 2019 Gravel joined Jason Johnson Racing in the No. 41 car. He finished third in the season-long World of Outlaws points standings and won two high-profile events: the Knoxville Nationals, the most prestigious crown jewel of sprint car racing held annually in Iowa, and the Jason Johnson Classic, named after the team's late founder who died in a racing accident in 2018. The 2019 season was the clearest demonstration to that point of Gravel's ability to win premier-level events.
In 2020 Gravel made two NASCAR Camping World Truck Series starts with GMS Racing, posting a best finish of tenth at Michigan International Speedway. He also made one ARCA Menards Series appearance that year, broadening his experience to asphalt oval racing before returning to full-time dirt sprint car competition.
Gravel moved to Big Game Motorsports and the No. 2 Maxim and has remained with that programme through his championship campaigns. He marked his 600th World of Outlaws feature start with a victory in the National Open preliminary at Williams Grove Speedway. He then won the World of Outlaws Sprint Car Series title in 2024 and defended it successfully in 2025.
Through the opening portion of the 2026 season — spanning 28 events — Gravel recorded five victories and nineteen top-five finishes, continuing his championship-pace form at Big Game Motorsports.