After filming, the Mustang was sold to a Warner Brothers employee, and later to a New Jersey police detective. He in turn sold it for $6,000 in 1974 to Robert Kiernan of Madison, New Jersey, who held onto the car until he died in 2014.
Kiernan rejected multiple offers for the car, including one from McQueen himself, according to the New York Times. He left it to his son, Sean.
"I would like to appeal to you to get back my '68 Mustang," McQueen wrote to Kiernan in 1977, according to the Times. "I would like very much to keep it in the family, in its original condition as it was used in the film, rather than have it restored; which is simply personal with me."
McQueen died in 1980 at age 50. Robert Kiernan never responded to McQueen's letter, which Sean Kiernan still has, the Times said.
Sean Kiernan told Mecum in a promotional video that his mother drove the car until the clutch failed in 1980. It went nearly 40 years without being driven until recently, with 65,000 miles on the odometer, Kiernan said.