Jack Tanzer, who died February 7 at age 83, was once a PR man for the New York baseball Giants who fed Frankie Frisch statistics for his radio broadcasts. He went on to become one of the leading art dealers in the city, specializing in Old Masters and numbering among his customers such connoisseurs as Armand Hammer, Imelda Marcos, and the Shah of Iran.

As president of the Old Masters division at M. Knoedler & Company, Tanzer was intimately involved in the painstaking negotiations involved when Hammer negotiated an unprecedented loan of 41 Impressionist and post-Impressionist works from the Soviet Hermitage museum at the height of the Cold War in 1973.

By all accounts, Tanzer was a master schmoozer. As a deal-maker, he was noted for complicated schemes that met multifarious demands. A former dealer at Knoedler, John Richardson, in his book “Sacred Masters, Sacred Monsters,” reported on the patter: “Throw in the little Renoir to sweeten things, he would cajole another dealer, and the Doctor [Hammer, owner of Knoedler] will let you in on the Eakins; or, give us a half share in the Canaletto, and Warhol will do a portrait of your wife. Tanzer could turn a minor Vlaminck into two Frank Stellas and, after a few more permutations, end up with a Rembrandt drawing.”

Tanzer’s family was from the Bronx, but he was born in Tuckahoe, where his family had fled while fearing an outbreak of whooping cough, Tanzer’s sister, Lilian Campo, recalled. Soon they were back in the Bronx, where Tanzer became a Giants fanatic and attended Evander Childs High School. A schoolboy artist, he apparently first got involved in professional art through an ad on a matchbook cover. At 18 he ended up as an animation intern for the Walt Disney Studio in Los Angeles.

With the outbreak of World War II, Tanzer decided to quit and return to New York to wait for his draft number to come up. The pay at Disney was so bad that he had to take a job washing dishes to pay for his ticket, his wife, Audrey Tanzer, said.

Tanzer ran sports cartoons in the Long Island Daily Advocate, a paper located in Ridgewood, and in 1942 briefly worked as a sports editor be fore being drafted into the Army Signal Corps.

After the war, he took a job with Art Flynn Associates, a public relations firm that represented several upscale brands (Longines, Gillette) and, most thrillingly for Tanzer, the Giants. He produced the daily “Giants Jottings” radio show for WMCAAM and toured with the team to help Frisch – known to New Yorkers who recalled his athletic prowess as the “Fordham Flash” – with game broadcasts. During spring training, it was Tanzer’s job to sign players to contracts with Topps, the baseball card company, Ms. Tanzer said.

When Willie Mays was a rookie on the Giants at age 20, Tanzer was assigned to look after him. He booked Mr. Mays on television shows and promotional appearances, but failed to prevent him from eloping to Maryland with a fashion model rumored to be a gold digger a few years later, Ms. Tanzer recalled.

The marriage did not last.

Sports had been Tanzer’s first love. It was inculcated by his father, a frustrated aspiring major leaguer, and nurtured by his holding any Giants fan’s dream job. Thus, in 1958, “he was heartbroken when the Giants left,” Ms. Campo said.

He briefly represented a chain of bowling alleys and did public relations for televised boxing matches, but his heart wasn’t in it.

Tanzer eventually reverted to art, his other talent. At first, he tried painting, especially during summer vacations on Monhegan Island, off the Maine coast. There, he was friendly with local artists, as well as with the actor Zero Mostel, with whom he shared a passion for pre-Columbian art.

In 1967, a chance meeting with Boston art dealer Warren Adelson led to a gallery partnership that quickly became a successful business. One important early client was the automobile heir Walter P. Chrysler Jr., whom Adelson helped to amass one of the outstanding American art collections. Chrysler eventually established a museum at Norfolk, Va.; among its collections are Tanzer’s pre-Columbian art, which he donated, and a portrait of Tanzer by Andy Warhol.

Of Tanzer’s relationship with Chrysler, Mr. Richardson wrote in “Sacred Monsters”: “Tanzer knew that Walter Chrysler, Jr. – a rogue whose excessive tax deductions for blatant fakes had been disallowed by the IRS – needed to acquire some respectable Old Masters on the cheap. And so he arranged for Chrysler to take a number of discredited paintings, which had been on Knoedler’s books for fifty years or more at huge valuations, in exchange for one superb Cezanne. This was a deal after Hammer’s own heart: nothing tickled the old tortoise as much as getting something for free.”

By this time, Tanzer had gone to work at Knoedler, in which Hammer had purchased a controlling interest in 1971. Because of his long and close relationship with the Soviet Politburo elite, Hammer was able to arrange for the Hermitage show, which moved on to the National Gallery in Washington, D.C., after being shown at Knoedler.

Among the gallery’s more celebrated customers was the Shah of Iran, who was so avid an art collector that Tanzer actually considered opening a branch gallery in Teheran to sell to the royal family, Mr. Adelson said. Imelda Marcos also bought at Knoedler. In 1990, when she was tried on charges of expropriating $222 million from the Philippines treasury, Tanzer testified that she had given Knoedler $2.2 million for a sculpture and four paintings, including “Trois Danseuse” by Edouard Degas.

After retiring from Knoedler in 1985, Tanzer opened his own gallery on East 72nd Street, where he continued to deal in the art he loved. Instead of Monhegan, he and his wife spent increasing amounts of time in Europe, especially Rome.

Jack Tanzer

Born December 16, 1921; died February 7 in New York of lung cancer; survived by his wife of 53 years, Audrey; his daughter, Tara, son, Edward, two grandchildren, three great-grandchildren, and his sister, Lilian Campo.