His mother, Hana Nancy Halper, said he had jumped off the Brooklyn Bridge.
“When he was making those hearts, he was making New York into a storybook that we might all want to live in,” the writer Lily Koppel, a close friend, said by phone. “To him, New York seemed to be losing its soul, and he was trying to put back its soul, and in the end I think it wore him out.”
Shortly before his death, Mr. Halper, who was also a painter, had been preparing for a solo exhibition at a venue on Hudson Street that would showcase his artwork. But, his family said, his paintings were destroyed during an altercation with someone who attacked him in his Lower East Side apartment. Rattled by the incident, he took to the streets and was seen two days later walking barefoot in SoHo.
After his death, people gathered at his favorite stoop on Prince Street to make a memorial with chalk hearts.
Tall and shaggy-haired, Mr. Halper could be seen wearing stylish hats or a red suit covered in hearts while he planted himself on streets for hours, bringing his hearts into existence with pieces of pink, blue and yellow chalk and a swift swoop of his hand. Over time, he became something of a downtown folk hero, cherished for his ability to conjure up positivity with a humble shard of chalk to an otherwise tumultuous city.
Once, when he learned that a woman was having a rough time with her romantic life, he began chalking hearts outside her workplace; she met someone special a few weeks later.