On a picture-perfect Sunday afternoon at the Guilford Yacht Club, a group of celebrants gathered to pay tribute to a man. Three weeks earlier, he had turned 180 years old.

More or less.

According to Stephen Davis, the oldest son of Madison philanthropist Jack Davis, his grandmother swore that Jack was born on July 18, 1923. His birth certificate, however, read July 20, 1923. It was only natural, then, that his family would observe his birthday on both days, making the white-haired bespectacled figure at the center of attention much younger than he appeared.

Suspect? Maybe. Then again, it may explain how the boy who once sold fruit on a pushcart on the Depression-era streets of Brooklyn has gone on to live a life of such variety and largesse that it might well fit two lifetimes.

There is the esteemed child psychologist who for 30 years acted as surrogate father to 1,500 teenagers struggling with emotional and social problems as executive director of the Grove School in Madison. There is the educational innovator who each morning doled out empathy and candy bars, his colleague George Olshin attested to the spirited crowd of 75 friends, family and elected officials.

And the sage businessman who, along with his wife Helen, founded Davis Realty in 1965, their sights set on making downtown Madison both an affordable living option and a cultural center.

There is the forward-thinking landlord who recognized that a downtown theater lends character to a town center. Hence, the independent Madison Arts Cinema which was born when then-operator Hoyts skipped out of town with its equipment, concession stand and seats.

There is “the quintessence of the renaissance man,” in the words of state Sen. Ed Meyer, lending his support to the Sculpture Mile, a world-class year-round outdoor museum of 25 installations that ranges from Stop & Shop Plaza to Main Street to Boston Post Road. Sponsored by the Hollycroft Foundation, it demonstrates, said Joan Baer, a leading force behind the endeavor, “Jack’s awareness of the importance of art in everyday life.”

When there existed the elusive dream of creating a place of worship, learning and social activity for Jewish families on the shoreline, it was Jack Davis who led the effort to make it a reality.

“If we will it,” Selectman Al Goldberg remembered him telling the group that would go on to found Temple Beth Tikvah, “we can make it happen.”

There is the father of three and grandfather of seven who stood in the way of developers eager to replace Garvin Point’s fragile ecosystem with lavish McMansions.

Quietly so. “Jack is a guy who wants to make a difference, not be the difference,” said renowned architect and author Duo Dickinson, crediting Davis with “nudging” him to form Madison Cultural Arts, a non-profit that organizes such events as summer and holiday concerts.

Which is not to say that the man whom Sen. Richard Blumenthal called “one of the greatest of the Greatest Generation” is a shy, retiring figure. Quite the contrary.

“Jack never takes himself too seriously,” said Dickinson. “But he believes passionately in what he does and sees it through.”

Added friend and neighbor Kirsten Adams, a realtor at William Sotheby’s: “every time I see him, he has another delightful anecdote that puts everything into perspective.”

That’s why people jetted in from as far as Paris and Washington, D.C. for the party; why Madison First Selectman Fillmore McPherson proclaimed Aug. 11, 2013 “Jack Davis Day”; and why, according to Rep. Joe Courtney, “the best birthday gift would be for us to try and follow his example.”

Not bad for a 180-year-old.