Sanford L. Smith, an art lover and entrepreneur who created some of New York’s most prestigious art and design fairs, generating millions of dollars in sales and drawing attention to previously overlooked areas of art, died on Saturday at a senior living facility in Manhattan. He was 84.

The cause was congestive heart failure, his wife, Jill Bokor, said.

Mr. Smith didn’t invent the art fair, but he made his events essential stops for both buyers and sellers. Owners of some Lower Manhattan galleries would spend tens of thousands of dollars to move their wares a few miles north to the Park Avenue Armory, where many of Mr. Smith’s shows were held.

Evan Snyderman, an owner of R & Company, a TriBeCa design gallery, said that at Salon Art + Design, one of Mr. Smith’s fairs, “we always reconnect with clients that we don’t see in other places — including New Yorkers who never come downtown.”

Some dealers reported selling more art in a long weekend at a Sanford Smith fair than in a whole year at their own galleries.

During his years in what he called “show business,” Mr. Smith ran more than 150 fairs, including the Fall Antiques Show, Modernism and the Outsider Art Fair. They were popular (in several cases attracting some 10,000 visitors over a three- or four-day weekend) as well as critical successes. The Times called his 2012 Salon “a museum in the making.”

Asked to describe his career in an interview for this obituary in 2022, Mr. Smith said, “I filled holes.” What he meant was that he found gaps in between what other art fairs offered, and created new events to meet those needs.

The Fall Antiques Show, which he founded in 1979, was the first such fair focused on American antiques. Then, on seeing the interest in work by self-taught artists at that show, he created the Outsider Art Fair in the early 1990s.

“In the New York City art and design worlds, Sandy was a one-man institution,” Paul Donzella, a Manhattan dealer in 20th century lighting and furniture, said in an interview in 2022.

“He showed incredible vision at a time when all of the fairs were the same old thing,” he added. “Modern design, outsider art, works on paper — no one was shining a light on these categories when Sandy took big risks on them.”

In his heyday, Mr. Smith produced as many as 11 fairs a year, sometimes two on the same weekend. He organized shows in Boston; Philadelphia; Princeton, N.J.; and Chicago, in addition to New York, which, he said, was “where the money was.”

Some of his fairs continue more than 30 years after he founded them, including a few that he sold to other companies.

How much money changed hands at his shows? Mr. Smith could not say, because dealers, who rented booths for a flat fee, didn’t report their sales. But the numbers would probably be astronomical. “In theory, an art show can sell a painting for $100 million,” he said.

What he did know, he said, is that “a lot of people made a lot of money at my fairs.” Those people included Mr. Smith, who in addition to collecting rent from dealers sold tickets to his shows for as much as $35 a day.

For many years he lived in a large brownstone on West 88th Street filled with paintings by such American modernists as Charles E. Burchfield and George Bellows and furniture by George Nakashima, Charlotte Perriand, Paul Evans, Alvar Aalto and Josef Albers, among others.

The brownstone also housed collections of antique weather vanes, toy soldiers and late 19th-century Austrian bronze figures of American Indians, three of the categories Mr. Smith said he “binged on.” His bingeing sometimes made him money, too.

Over the years he sold his collections of American pewter, American spongeware and works by George Ohr, who was known as the “Mad Potter of Biloxi,” to collectors. Why sell? “The fun was in the hunt,” he said.

Sanford Louis Smith was born in Brooklyn on July 22, 1939, the first of two sons of Irving and Rhoda (Levinson) Smith. His father (born Israel Smith) ran the Zion Memorial Funeral Home on Canal Street in Manhattan while his mother managed the household.

Mr. Smith began collecting as a child — baseball cards and comic books. He majored in economics at the Wharton School of the University of Pennsylvania, then received a master’s degree in communications from the University of North Carolina at Chapel Hill.

He was offered a job by Procter & Gamble in Cincinnati. But, he recalled: “My father offered me more money, plus a car, to come into the family business. And I got to stay in New York. So I took him up on it.” By that time he had married Patricia Lynch, whom he met in college. The couple had three sons.

After their father died, he and his brother continued to operate the funeral business.

“I was never a mortician,” Mr. Smith said. “I did the numbers. But I was bored out of my mind.” The funeral business, he wrote in an unpublished memoir, “is for lazy people. You can’t go out and solicit someone to die.”

So he found another outlet for his love of business. On his off hours he combed antique shops in Greenwich Village, and he turned weekend visits to his in-laws in Connecticut into shopping expeditions. What couldn’t fit into his in-laws’ garage or the basement of the funeral home, he and his wife sold at a flea market at West 26th Street and Sixth Avenue.

He told The Times in 2019 that in those days, the 1960s, renting a flea market stall cost $15. “The first time we did it, we made $50 net. I said, ‘This is for me.’”

During those years he also wrote books about painters he admired and made Art Nouveau and Art Deco jewelry that he sold out of the funeral home. At one point he had an art gallery on Madison Avenue. Later, he began selling Viennese bronze animals, movie lobby cards and painted country furniture at art fairs. (In those days, fairs were generally held at Madison Square Garden or in the New York Coliseum.)

Eventually he decided he could run a better fair. “I saw that the managers weren’t taking care of their exhibitors. As soon as they got the gate” — meaning the ticket revenue — “they ran.” Mr. Smith had ideas for improvements: providing free coffee to everyone working at the fair, and hiring enough people to handle dealers’ complaints promptly.

Over the years Mr. Smith raised millions of dollars for charities by allowing them to sponsor gala previews of his shows.

He created his first fair, the Fall Antiques Show, in 1979. “I ran it out of the funeral home,” he recalled. That show ran for 21 years.

Modernism came along in 1985 and lasted until 2010. In 2011, it was replaced by the Pavilion of Art & Design. But Mr. Smith had a nasty public feud with Patrick Perrin, the founder of the original Pavilion, which was in Paris. According to The New York Observer, each man circulated a letter during the fair’s run, asking that participating dealers promise never again to work with the other.

The following year, Mr. Smith replaced Pavilion with his own creation, Salon Art + Design (which, per its name, was one of the few fairs to mix art and utilitarian objects). He hired Jill Bokor, a former design magazine publisher who had become his wife after Ms. Lynch died, as Salon’s executive director.

In addition to Ms. Bokor, he is survived by four sons: Colin, Jared and Ian, from his first marriage, and Luc Bokor-Smith; and five grandchildren.

His other fairs included Works on Paper, now called Art on Paper; the National Black Fine Art Show; the Aipad (Association of International Photography Art Dealers) Photography Show; the New York International Antiquarian Book Fair; the Art Dealers Association of America Art Show; the Philadelphia Antiques Show; the New Jersey Antiques Show; the International Fine Print Dealers Association Print Fair, and the Chicago Art + Antiques Show, now called The Chicago Show: Antiques & Art & Modern.

“Every fair I’ve ever done has been profitable, from Day 1, ” Mr. Smith said in 2022. But his success was more than just financial. “I give him a lot of credit,” Mr. Donzella said, “for creating these fairs and for staying relevant for so long.”