Ken Milburn of Windsor, Ontario, says the gloves have been in his family since Schmeling's 12th-round knockout of Louis at New York's Yankee Stadium in 1936, the Canadian Broadcasting Corp. reported Friday.
Although they would be a valuable collector's item, Milburn told CBC Radio he never even considered selling the gloves.
"The bottom line is, they're not for sale," Milburn said. "They could be worth 2 cents, they could be worth 2 million, who really cares?"
He said he tried to donate them to the International Boxing Hall of Fame, but after three phone calls, "they didn't call back." Ditto the Canadian Amateur Boxing Association, he said.
But the third try was a charm. Milburn said when he called the Smithsonian, he received an instant and enthusiastic response.