“The longer he kept working, the more famous he got,” said Jane Dinezza , the owner of Fantastic Cuts in New Windsor, the last salon where Mr. Mancinelli worked.

Over time, she said in a phone interview, she became less of his boss and more of a liaison to media outlets, as reporters started showing up to interview him, seating him in his own barber chair. “He was spending more time in the chair than his customers,” Ms. Dinezza said.

Instead of paying the usual $20 for a haircut, many customers would insist on giving him up to $100 a cut, she said. And he was invited to so many events, she said, “I started saying, ‘No, I’m sorry, it’s just too much hoopla for him — you know, he’s not the pope.’”

Mr. Mancinelli retained a trim build, a steady hand and a full head of snow-white hair. Even in his final years he spent long hours on his feet, in a pair of worn, cracked black leather shoes.

His good health baffled his doctor, he said. He was on no daily medication and never wore glasses.

“He never took a pill in his life,” Ms. Dinezza said. “Towards the end, people would follow him through the grocery store just to ask him the secret to living that long. He’d just point up to God.”