In 1962, Key West, Fla., was a remote naval outpost on six square miles of limestone rock, mostly known for its proximity to Cuba at the height of nuclear tensions with the communist island. Rickety wood-frame houses lined its streets, at times threatening to collapse. The declining waterfront, once a busy trading port, offered visitors little more than a selection of weather-beaten bars.

David Wolkowsky, a developer who had returned to the city of his birth after years away, saw opportunity. For the next few decades, he devoted himself to the task of restoring the island’s dilapidated historical buildings, eventually helping Key West become a major resort destination.

Mr. Wolkowsky, 99, who became widely known as “Mr. Key West” for his role transforming the island, died Sept. 23 at a hospital in Key West. The cause was complications from pneumonia, said a nephew, photographer Timothy Greenfield-Sanders.

By salvaging turn­of-the-century homes, Mr. Wolkowsky helped ensure that the city of 25,000 retained a distinctive sense of character. Key West has an enduring eccentricity that prevents it from being just another wealthy seaside town: Free-range roosters wander the streets with impunity, bougainvillea sprouts from yards with wild abandon, and a year-round crew of crusty burnouts provide a welcome contrast to the tourists lining up for fudge and trolley tours.

Instead of high-rise condominiums, the city offers something rarely found elsewhere in Florida: a sense of history.

“David began to renovate those buildings and really, I think, was one of the main people responsible for the historical preservation movement and for showing people that Key West’s past, its history, was worth saving, had a certain glamour to it, was beautiful,” Arlo Haskell, a local historian, told Miami-based radio station WLRN this week.

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Mr. Wolkowsky’s own family was deeply embedded in that history. His grandfather Abraham was a Jewish immigrant from Russia who first arrived in Key West in the early 1880s and quickly went from being a street peddler to becoming a successful local merchant. The family business eventually included clothing stores, saloons and a billiards hall.

David William Wolkowsky was born in Key West on Aug. 25, 1919. Several years later, the city went through an economic slump after a devastating hurricane hit the island and the Navy pulled out many of its operations in the wake of World War I.

“We left on the train when I was 4 and moved to Miami,” Mr. Wolkowsky told the Key West Citizen newspaper. “I can remember eating guava jelly on Saltine crackers in the dining car of the train.”

After attending the University of Pennsylvania, he spent four years in the U.S. Merchant Marine and settled in Philadelphia. Under the name David Williams — to avoid anti-Semitism — he began renovating and rehabilitating shabby rowhouses near Rittenhouse Square in Center City, participating in Philadelphia’s inner-city renaissance.

Mr. Wolkowsky was 42 when his father died, and he inherited a handful of aging buildings in Key West. He bought up more underappreciated properties, including a former cigar factory, a bar where writer Ernest Hemingway used to drink and an old department store.

His efforts to preserve and protect ramshackle buildings went against the conventional wisdom of the 1960s. Throughout the country, cities were bulldozing blighted neighborhoods in the name of urban renewal. Walkable, tightly packed commercial strips such as Key West’s Duval Street were falling out of favor and were quickly being replaced by shopping centers with ample parking.

Mr. Wolkowsky instead chose to invest in Key West’s historic Old Town. In 1968, he opened the Pier House, a waterfront hotel where Jimmy Buffett played some of his earliest dates. With a keen sense of public relations, Mr. Wolkowsky invited literary celebrities, including Tennessee Williams and Truman Capote, to come and stay — and got national magazines to photograph them at the hotel.

Williams, who later settled in the city, “was the best PR person for Key West back then,” Mr. Wolkowsky told the Key West Citizen. “He brought the likes of Vivien Leigh, Gary Cooper and many others to Key West.”

Many years later, the Miami Herald identified the opening of the Pier House as “the turning point in Key West’s transformation from washed-up military outpost to funky tourist destination.” In the late 1970s, Mr. Wolkowsky sold the hotel for $4.6 million and invested in other properties.

Survivors include a sister.

Typically dressed in Panama hats and crisp white linen shirts, Mr. Wolkowsky rode around Key West in golf carts and a vintage Rolls-Royce. In 1974, he purchased Ballast Key, a small rocky island located roughly eight miles from Key West.

“I used to come out and picnic here when it was a deserted island,” he told the Fort Lauderdale Sun-Sentinel in 1983. “And I’d see people cutting down these mangrove trees which took decades to grow, cutting them to make hot dog fires, and I’d get annoyed. Then I got interested in buying the island to protect it.”

In August, Monroe County commissioners voted to rename the island “David Wolkowsky Key.” The name change has not been made official, as the U.S. Board of Geographic Names doesn’t consider applications until five years after a person has died.