Billy Joe Hagan was born in Lillie, Louisiana. He made just three starts in NASCAR's Grand National/Winston Cup division, finishing eighth first time out in the inaugural Talladega 500 driving his own 1968 Mercury.
Hagan was better known as a team owner, fielding cars in 547 races between 1969 and 1994.
In 1976, he ran the Stratagraph Chevrolet for Skip Manning, who won Rookie of the Year honors. Manning was released in 1978 and Billy hired Terry Labonte for five races that year. Labonte was fourth on his debut, the Southern 500 at Darlington, and went on to finish 10th in the standings the next year. Together they finished in the top 10 every year for the next four years before winning the NASCAR Winston Cup championship in 1984.
Labonte left the team in 1986 and was replaced by Sterling Marlin who had 19 top-fives in 116 races with Hagan the next four years.
Labonte returned in 1991, but was unable to rekindle their success. 1994 was Hagan's last season, running cars for John Andretti and Randy MacDonald.
In 1996, he sold out to Triad Motorsports but continued to serve as a co-owner of operations until the team's demise in 1999.