Swedish director Malik Bendjelloul was in South Africa looking for a subject to use for his next film. “I was traveling around for six months in Africa and South America,” he said, “looking for good stories and reading a lot of articles.”

Bendjelloul eventually met South African businessman Steven Segerman, who explained that, for decades, he and millions of South Africans had been fans of an American singer named Rodriguez. Not only were they fans, they thought Rodriguez was one of the greatest singers to have ever lived. The legend was that the American singer had somehow killed himself onstage after releasing only two albums. As Bendjelloul listened to the story, he realized that “this was the best story I have ever heard in my life!” He went on to make a documentary about it titled “Searching for Sugar Man.”

Indeed, while Rodriguez is considered to be one of the greats in music history by many South Africans, in the United States, Rodriguez is a nondescript denizen of Detroit who uses his hands not to strum guitars, but to pour concrete. His immense fame was completely unknown to everyone in the United States, including Rodriguez himself. It wasn’t until 1998, when he got a call from a South African reporter who was initially trying to find out how he actually died, that he learned of his fame overseas.

What Rodriguez found out was that his music was the soundtrack for white liberals’ efforts to help end the ugly apartheid system in South Africa, and it remains popular there today. Rodriguez gave up pursuing a music career after being dropped by his record company when his second album, like his first, bombed in America. It is not clear how his music initially got to South Africa. The singer and guitarist, who counts Bo Diddley and Ray Charles as major influences, then became a construction worker, family man and community activist.

Despite finding out all of this, Rodriguez remains unchanged. He carries with him a somewhat otherworldly bearing, but it is more a consequence of his own deep belief in the dignity of himself as a human being than anything else he may have done or how many people admire him. He has played to sold-out audiences in South Africa many times since the fateful call in 1998 and has given away the bulk of the proceeds from those concerts. After a screening of Bendjelloul’s documentary at the recent Tribeca Film Festival, there were murmurs among audience members about the Mexican-American singer’s almost “Christlike” level of humility.

Of South Africa, the soft-spoken Rodriguez says his knowledge was very limited before traveling there, and he has thus far taken four trips. He describes himself as being “keen on the place.” Still, his eyes were opened to the lingering inequity that is still a reality in many parts of South Africa today. He remarked, “This thing ain’t done, [there’s] been progress, but it’s not fixed yet.”

“Searching for Sugar Man” will be released in New York and Los Angeles this summer.