The identity of the buyer in the online auction, which ended Tuesday, was not disclosed. The comic book, Action Comics No. 1 from June 1938, was the first appearance of the all-American superhero by writer Jerry Siegel and illustrator Joe Shuster.
It had been estimated to sell for about $100,000, Comicconnect.com CEO Stephen Fishler said, adding that there are about 100 remaining copies of the 250,000 original copies.
"It's so noteworthy because it was a historic milestone," Fishler told Reuters. "There was no such thing as a superhero or a man in costume (in 1938)."
The comic book was sold by building contractor David Gonzalez, who discovered it among newspapers used as insulation in a wall during a home renovation in Hoffman, Minnesota, about 150 miles northwest of Minneapolis.
Gonzalez bought the vacant 1938 home for $10,100, Fishler said.
The book's condition was graded 1.5 out of 10 because its back cover was accidentally ripped shortly after it was found.
"Conservatively, that's a $50,000 tear, but probably more," Fishler said.
A mint condition copy of Action Comics No. 1 would command about $3 million, Fishler said. A 9.5 graded copy of Action Comics No. 1 sold for $2.16 million in 2011.
Superman gets a big-screen reboot in the movie "Man of Steel," which opens in North America on Friday.