Description Available in: William McComas Byron Jr. (born November 29, 1997) is an American professional stock car racing driver. He competes full-time in the NASCAR Cup Series, driving the No. 24 Chevrolet Camaro ZL1 for Hendrick Motorsports, part-time in the NASCAR Xfinity Series, driving the No. 17 Chevrolet Camaro for HMS, and part-time in the NASCAR Craftsman Truck Series, driving the No. 51 Chevrolet Silverado for Kyle Busch Motorsports. He won the 2015 NASCAR K&N Pro Series East Championship and the Sunoco Rookie of the Year award in the 2016 NASCAR Camping World Truck Series season. The following season he won both the 2017 NASCAR Xfinity Series Championship and 2017 Sunoco Rookie of the Year. Byron also won the 2018 MENCS Sunoco Rookie of the Year award.