William McComas Byron Jr. is an American professional stock car racing driver. He competes full-time in the NASCAR Cup Series, driving the No. 24 Chevrolet ZL1 for Hendrick Motorsports, and part-time in the NASCAR Xfinity Series, driving the No. 17 Chevrolet Camaro for Hendrick. 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. He is the 2024 and 2025 Daytona 500 winner.