Peter Massie, a movie buff, found the 10-minute movie, "Their First Misunderstanding," while clearing out an old barn in Nelson, N.H., before demolishing it, the New Hampshire Union Leader reported last week.
He brought it to Keene's film department.
"I was up in the attic, and tucked away over in a corner was some film, film canisters and a silent movie projector," Massie said. "I thought it was really cool. I always look around before a demolition. You never know what you'll find."
Larry Benaquist, who founded the film program, said the movie is considered so significant the Library of Congress funded its restoration.
Pickford -- one of the great stars of the silent era, when she was known as "America's Sweetheart" -- was married Douglas Fairbanks, the dashing hero of many silent movies. The couple were dubbed "Hollywood royalty," reigning from their mansion, Pickfair.
Both their careers stalled with the advent of sound, and the marriage also ended. Pickford stayed on at Pickfair, marrying actor-bandleader Charles 'Buddy' Rogers and adopted two children with him. She died in 1979 at age 87.
Keene plans to show "Their First Misunderstanding" publicly Oct. 11.