Julius (Slick) Johnson, 41, critically injured in a crash Sunday at Daytona International Speedway, died Wednesday night at Halifax Medical Center.
A hospital spokesman said Johnson, of Florence, S.C., was declared brain dead at 6:50 p.m. PST.
Johnson suffered a broken skull and chest injuries in the multi-car crash late in the Daytona ARCA 200 stock car race, an annual event sanctioned by the Automobile Racing Club of America.
Johnson had been on a respirator since Sunday night and was being given medication to maintain his blood pressure.
Johnson's death is the 23rd fatality resulting from accidents at Daytona International Speedway, including Dale Robertson, a go-kart driver killed in December.
Johnson was the first stock-car driver to die from injuries sustained on the 2.5-mile oval since Joe Young was killed in 1987.
The list of fatalities includes 12 stock car drivers, two championship car drivers, a powerboat driver--on the infield's Lake Lloyd--a test car driver, one sports car driver, three motorcycle riders, two go-kart drivers and one spectator.
Mike Staley, a track safety worker injured in the Johnson accident, was reported in serious but stable condition with a broken and burned left forearm and a broken left leg.