Hailie Deegan started in off-road trucks with Metal Mulisha support, racing Junior 2 in the Lucas Oil Off Road Racing Series. Brian Deegan's daughter was known as the Dirt Princess in those early years. She practiced and raced while her dad was competing in Pro Lite, then moved from dirt into stock cars.

At Meridian Speedway in 2018 she became the first woman to win a NASCAR K&N Pro Series race. She added two more wins in 2019, and all three came from passes on the final lap. She also began racing ARCA in 2019, earning four top ten finishes in six starts before joining Ford's development program.