Johnson's death was confirmed by the NASCAR Hall of Fame, according to the NASCAR website. The website said his health had been declining and entered hospice care earlier in the week.
Johnson was inducted into the NASCAR Hall of Fame in its inaugural Class of 2010. He won 50 races in NASCAR's top division and added 132 victories and six championships.
"Junior Johnson truly was the 'Last American Hero,' " NASCAR Chairman and CEO Jim France said in a statement. "From his early days running moonshine through the end of his life, Junior wholly embodied the NASCAR spirit. He was an inaugural NASCAR Hall of Famer, a nod to an extraordinary career as both a driver and team owner. Between his on-track accomplishments and his introduction of Winston to the sport, few have contributed to the success of NASCAR as Junior has. The entire NASCAR family is saddened by the loss of a true giant of our sport, and we offer our deepest condolences to Junior's family and friends during this difficult time."