The man who sang it in a croaky voice, accompanying himself on the accordion and glockenspiel, was known as Bruno S. He was a street musician, a painter of pictures, a forklift operator in a steel mill and, at one time, a mental patient. But, perhaps most remarkably, he was the lead actor in a movie that won the Grand Jury Prize at the Cannes International Film Festival in 1975.
His full name, which he seldom used, was Bruno Schleinstein. He died Wednesday at the age of 78 in Berlin, according to the German Press Agency, quoting his friend the artist Klaus Theuerkauf.
Werner Herzog, one of the innovators of postwar German cinema, twice in the 1970s cast Bruno to play pretty much himself a damaged but somehow transcendent character.
The first of those films, the one that won at Cannes, was “The Enigma of Kaspar Hauser” (1974), based on a true story. In the film the character played by Bruno appears in a square in 19th-century Nuremburg. He cannot speak and can barely stand, having apparently been kept in a kind of dungeon. The only clue to his identity is a paper giving his name as Kaspar and asking that he be taken into service as a soldier.
Kaspar is taught to speak and to read and write, and then, in a fashion as mysterious as his appearance, he is murdered.
Bruno’s acting moved Richard Eder of The New York Times to write: “Kaspar’s extraordinary face, his eyes strained wide to see better, his whole posture suggesting a man trying to swallow, trying to grasp a world of strangeness, is the film’s central image.”
As he learns to speak, Kaspar finds much of society repulsive. “Every man is a wolf to me,” he says. He has no ego: “Nothing lives less in me than my life.”
“The story of Kaspar is more fascinating than the story of Jesus Christ,” Anaïs Nin was quoted as saying in an advertisement for the film.
Bruno Schleinstein was born on June 2, 1932, most likely in Berlin. Some accounts say his mother, a prostitute, had beaten him so badly when he was 3 that he became temporarily deaf. This led to his placement in a mental hospital, where he was the subject of Nazi experiments on mentally disabled children.
Nobody visited him, not even relatives he knew. He spent 23 years in institutions, including jails and homeless shelters. When on his own, he broke into cars for a warm place to sleep.
As an adult he held various jobs, including forklift driver, and began to sing in courtyards around Berlin in the oral tradition that inspired Brecht’s “Threepenny Opera.”
He didn’t sing songs, Bruno said; he transmitted them. One song, “Thoughts Are Free,” concerned the impossibility of finding refuge even in one’s thoughts.
Mr. Herzog first glimpsed Bruno in a 1970 documentary about street musicians.
“I instantly knew he could be the leading character in ‘Kaspar Hauser,’ ” Mr. Herzog said in an interview with NPR in 2006. Bruno did not want his name known, and so Mr. Herzog began calling him “the unknown soldier of cinema.” During filming, Mr. Herzog said, Bruno would have moments of “utter despair” and start talking, sometimes screaming, in the middle of a shot and continue in that way for two hours.
Bruno’s second film, “Stroszek” (1977), was based on his life; Mr. Herzog had written the script expressly for him. Some scenes were shot in Bruno’s own apartment. In the film, Bruno, a prostitute he befriends and his aging landlord move to the mythical Railroad Flats, Wis., where they live in a trailer.
In the film, Bruno, who refers to himself in the third person, has sharp comments about America. “Bruno is still being pushed around,” he says, “not physically but spiritually; here they hurt you with a smile.”
Bruno said in interviews that he had never wanted to be a movie star, and in time the benefits of fame faded, other than the occasional free haircut by a friendly barber.
“Everybody threw him away,” Bruno said of himself.
He continued to carve out a life with his music and artwork, some of which was compelling enough to be exhibited at shows of so-called outsider art, including one in New York. When playing for street audiences, he never asked for money. Sometimes a friend would pass a hat for him. He drew a small pension. He apparently had no survivors.
In 2002, the German filmmaker Miron Zownir made a documentary called “Bruno S. Estrangement Is Death.” In it, Bruno seems to answer the many who worried that he had been exploited by Mr. Herzog.
“I have my pride, and I can think,” he said, “and my thinking is clever.”