He let the Bullitt go with a bang.

The iconic green Ford Mustang from the 1968 Steve McQueen thriller “Bullitt" was sold for $3.4 million at the Mecum Auctions event in Kissimmee, Fla., Friday. It was the latest chapter in the long-lost car’s story, which may be even better than the movie.

The custom 1968 Mustang GT 390 is one of two -- a dedicated stunt/camera car and this one that McQueen drove for his close-ups -- that were used during the making of the film, known for its legendary chase sequence through the streets of San Francisco. The damaged stunt car was reportedly sent to the crusher after production wrapped, while the hero car ended up in a Road & Track classified ad in 1974 and was bought for $3,500 by a New Jersey man named Robert Kiernan for him and his wife to use as a daily driver.

Three years later, Kiernan got a letter from McQueen asking to buy it back. The Kiernans told him thanks, but no thanks, and drove the car regularly until 1980 when the clutch went out with 65,000 miles on the odometer. It was then parked in the couple's garage. Robert planned to get it fixed one day but never did. The Kiernans and their two children, Kelly and Sean, eventually moved to Tennessee and brought the Mustang with them, but eventually put it in storage, where it deteriorated over many years.

With the growth of the Internet came speculation over the fate of the "Bullitt" Mustang. As the Kiernans learned about the interest in the car, they realized they had something special, but they weren't ready for the the attention it would bring them. So they kept it hidden and a secret from nearly everyone.

Sean said they often talked about restoring the car and going public, but before they had the chance, Robert came down with Parkinson’s and died in 2014. Then, as the 50th anniversary of the film approached, Sean decided it was finally time to share the car with the world. He reached out to Ford, who helped him get it running. The car made its return at the 2018 Detroit Auto Show, where it was used to help unveil the "Bullitt" tribute edition of the new Mustang.

At the time, Sean said he wouldn’t let the car go for any amount. But after taking some time off from work to travel the world with it to automotive events, he concluded that selling it could be a game-changer for his family and chose to bring it to Mecum, where he drove it onto the auction block with Kelly beside him as the bidding opened at a ceremonial $3,500.

The offers spiked to $3 million within three minutes and the hammer eventually came down on a $3.4 million bid, the second-highest price ever paid for an American muscle car, according to Hagerty. The identity of the buyer has not yet been disclosed, but whoever it is is on the hook for $3.74 million after auction fees are added on.

"I feel really good," Kiernan told NBC Sports after the auction. "The whole family's happy."

"What a way to end this."

The stunt car has got quite a history of its own. It was accidentally discovered rotting away in a Mexico junkyard in 2017 by a California man named Hugo Sanchez. He was looking for a Mustang to turn into a clone of the “Eleanor” car from the film “Gone in 60 Seconds." The car was identified as the “Bullitt” car by modifications made to accommodate cameras and lighting equipment.

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After giving it a hasty restoration, Sanchez and the car’s co-owner, Ralph Garcia, are currently in the midst of bringing it back to its on-screen condition and plan to bring it to an auction when the job is done properly.