For every Redbone, the ’70s rockers who openly embraced their Indian roots, there were dozens of others who did not. For many, there was little upside to it. “Around the time when ‘Rumble’ came out, there was the Hayes Pond incident, where this Grand Dragon was preaching from the backs of trucks about the ‘mongrelization’ of white people by American Indians,” Ms. Bainbridge said, referring to a North Carolina confrontation between the Klan and the Lumbee. “Link Wray grew up in the center of all that, as did Native Americans throughout the South.”

The film was inspired by “Up Where We Belong: Native Musicians in Popular Culture,” an exhibition that was first mounted at the Smithsonian’s National Museum of the American Indian in 2010. It soon became one of the museum’s most popular. Curated by Mr. Salas and Tim Johnson, the museum’s program director at the time, the exhibition, with its rock videos and battle-ax guitars, was a marked departure from previous shows. “They certainly didn’t want to include Randy Castillo, the drummer from Ozzy Osbourne,” Mr. Salas said.

Buoyed by the success of the show and the stories the Smithsonian was able to uncover, the curators immediately thought: This needs to be a documentary. They sought out Ms. Bainbridge, who had gotten critical acclaim for the 2009 documentary “Reel Injun.” That film examined the portrayal of Native Americans in Hollywood, many of them played by nonnative actors. “We found this way, through humor, for people to relate,” she said. “I thought we’d never have that chance again, to make a film that could really cross over. But as it turns out, music is even more powerful than comedy.”

Throughout, the film reveals how Native American rhythms and stylings became a part of the larger tapestry of American music. In one scene, the poet and musician Joy Harjo (“Crazy Brave”) explains how the call and response of Muscogee music influenced the evolution of jazz and blues; in another, the singer-songwriter Pura Fe connects the blues guitar and vocal inflections of Charley Patton, who was probably of Choctaw ancestry, with traditional Indian music.