"Only one person knows the buyer, and that's the guy he was on the phone with," explained Sean Kiernan, who auctioned off the highland green Mustang on Friday in Kissimmee, Florida. "Eventually, it'll come out. But right now, no one knows."
The famed Mustang ultimately sold for $3.4 million, plus fees and commissions, which brought the total to $3.74 million, the outlet reported. Frank Mecum, showrunner of the world-renowned event at Mecum Auctions, is the only person who knows the buyer's identity.
The sale marks the most expensive Mustang ever sold, surpassing a 1967 Shelby GT500 Super Snake that sold last year for $2.2 million, the Orlando Sentinel reported.
Kiernan, 38, estimated 7,000 people attended the auction, where bidding started at $3,500 – what the price his father paid.
Kiernan's father, Robert, bought the car after seeing an ad in a 1974 issue of "Road & Track." The New Jersey family used it as a daily commuter until the clutch gave out in 1980. In the late 1970s, McQueen, who played the title character in "Bullitt," tracked down the Kiernans and asked if he could reclaim the muscle car in return for a similar Mustang. His pleas went unanswered.
Bidding surpassed $3 million in the first minute. The top bid went back and forth between someone present and a bidder on the phone for several minutes before the mystery buyer on the phone won.
"When the auctioneer asked, 'Who will give me $3,500?' Everybody in the room raised their hand. Everybody had a chance to bid on the car," he recalled, according to the report.
Before he sold the Bullitt, Kiernan reportedly took the car on a two-year tour across the globe.
"As far as Mustangs go, this is it. With dad being down in the record books forever, that's what matters to me," he said. "I've been at peace with the sale for probably eight months now. We're just having fun with this."
The Associated Press contributed to this report.