Mayer got off to an early start in racing, competing in go-kart events at the age of four. Although his father, Scott Mayer, was an open-wheel racer, Sam chose in his preteen years to focus on stock car racing. Over the course of the 2017 summer, during which Mayer turned fourteen, he spent the summer in Charlotte to race Legends cars; he won the Young Lions division of the Charlotte Motor SpeedwaySummer Shootout. He also raced in a Limited Late Model and won at Greenville-Pickens Speedway to become the track's youngest winner. He came back to Wisconsin and won a September Midwest Truck Series race at Dells Raceway Park in his first series start. Over the middle of 2017, he came in touch with industry veteran Lorin Ranier, who eventually landed Mayer a late model ride with JR Motorsports in the CARS Tour for 2018. Mayer's late model racing also brought him to the World Series of Asphalt, where he finished second to Stephen Nasse. Ranier also led Mayer to MDM Motorsports for a limited slate in the ARCA Racing Series and NASCAR K&N Pro Series East in the back half of 2018, with age restrictions being a factor in which races Mayer could run, as both series only let 15-year-old competitors race on certain tracks. In his first ARCA race, Mayer ran as high as third and finished inside the top-ten. After the CARS Tour season was over, Mayer was voted the series' Most Popular Driver for 2018. The CARS Tour season included one victory, at Wake County Speedway. On December 5, 2018, it was announced that Mayer would run a full NASCAR K&N Pro Series East schedule with GMS Racing as part of a 2019 schedule that would also include seven ARCA races and four NASCAR Gander Outdoors Truck Series races with the team. All four of the Truck races will come after Mayer turns sixteen; his debut is slated to be at Bristol Motor Speedway in August. That race would be followed by appearances at Canadian Tire Motorsport Park, Martinsville Speedway and ISM Raceway. Mayer scored his first K&N East win at Bristol on April 6, 2019, leading every lap. He nearly scored his first ARCA Menards Series win at Gateway in June after a late pit gamble, but was moved up the track by Ty Gibbs in the final set of corners and was relegated to third. In October, he won the 2019 K&N East championship to become the youngest NASCAR champion at 16 years, 3 months, and 8 days; the previous record was 16 years and 5 months by Todd Gilliland in 2016. Mayer ended the 2019 season with four wins and top tens in all but one race.
Motorsports career results
NASCAR
Gander RV & Outdoors Truck Series
Season still in progress Ineligible for series points
