Michael Perlman should start charging a commission.

On Monday, the 25-year-old from Queens announced that he had just brokered a deal to move midtown’s Cheyenne Diner to the Brooklyn waterfront.

Hey, it was either Red Hook—or the wrecking ball.

Just two weeks ago, the 68-year-old all-night diner on Ninth Avenue near Penn Station had served what appeared to be its final triple-decker burger. Landlord George Papas, who also owns the nearby Skylight Diner, planned to tear down the shiny, chrome-covered, prefab single-story railroad-car-style structure and erect a nine-story apartment building in its place.

Then Mr. Perlman stepped in, convincing Mr. Papas that he could find a buyer to relocate and restore the old neon-lit eatery, preferably some place else in New York City.

Mr. Papas initially agreed to sell the would-be scrap heap for around $7,900—a sum that Mr. Perlman said “reflects the urgency of removing it from the property so development plans can proceed.”

The landlord ended up unloading it for just $5,000 to construction manager Mike O’Connell, son of Brooklyn developer and major Red Hook landowner Greg O’Connell.

“It will gain a new lease on life in Red Hook, Brooklyn, and contribute to the appeal of an up-and-coming neighborhood,” Mr. Perlman proudly announced via e-mail on Monday, then delved into the wonky specifics of the tricky relocation ahead: “The immediate steps will be to confirm a rigger ... and then apply for demolition permits, which is a mandatory precursor to disconnecting utility lines and lifting the diner from its foundation, amongst other requirements.”

It’s the second time that Mr. Perlman has brokered one of these diner-relocation deals in New York City, which is all the more remarkable because he isn’t really a broker. At least not professionally.

A freelance writer, part-time administrative assistant and solo cabaret performer, Mr. Perlman fights to save historic places from destruction in his spare time. His efforts have generated a lot of publicity.

Most notably, last August, he helped find a new home for Soho’s long-standing Moondance Diner, the gleaming greasy spoon with the iconic crescent-shaped logo where Kirsten Dunst’s character, Mary Jane, waited tables in the 2002 summer blockbuster Spider-Man—and which, just like the Cheyenne, was about to be bulldozed in the name of development.

How appropriate, then, that its savior would swing in from the fictional web-slinging superhero’s own neighborhood of Forest Hills.

Mr. Perlman’s Committee to Save the Moondance Diner, in collaboration with the nonprofit American Diner Museum in Providence, R.I., ultimately located a buyer who, for just $7,500, drove into town on a flatbed truck and hauled the factory-built eatery off to La Barge, Wyo., where it’s expected to reopen this summer.

The sale and relocation, which was widely chronicled by news outlets across the country, was a pivotal moment for Mr. Perlman. “That was the effort that made me an official New York City preservationist,” he said.

“He’s just a force of nature, a one-man dynamo, and I think we all owe him a great debt of gratitude for the incredible work he’s done,” said Andrew Berman, executive director of the Greenwich Village Society for Historic Preservation, who puts Mr. Perlman at the forefront of “a new wave” of activists concerned with safeguarding various New York institutions.

“It’s a new kind of historic preservation compared to what you’ve typically seen in New York,” Mr. Berman said. “It’s not about some 19th-century Renaissance palazzo that’s being demolished. It’s about this coffee shop or this bar or something like that, which is every bit as real in terms of the way people connect to it in terms of their sense of the history and the character of the city, but it’s not necessarily your standard architectural or historic gems. It’s more these little slice-of-life places.”

“A diner is the ultimate public institution,” Mr. Perlman explained over lunch last week at his local hangout, the Tower Diner on Queens Boulevard, where everyone, from the hostess to the waiter to the owner, seemed to know him by name. “Lately, that particular slice of New York City history is becoming endangered most rapidly.”

Throughout the interview, the LaGuardia High School and Marymount Manhattan College graduate demonstrated an encyclopedic knowledge of facts and figures about various city landmarks.

During lunch, he paused to peer out the window and ponder the fate of the old Jay Dee Bakery across the street. “Jay Dee Bakery has been here since the 1950s,” he said, noting its “old-school illuminated reverse-channel sign,” its “Art Deco-inspired” design, and classic cake display. “Very ’50s-ish,” he said. “Rumor has it that they’re going to shutter.”

Later that afternoon, he got in touch with the owner, who clarified that the bakery was not for sale, just closed temporarily while management sought out a new partner in the business. “Now I’m a man with a mission who’s hoping to find him a partner, in order to ensure many successful years ahead,” Mr. Perlman said.

“I’ve always been a preservationist at heart,” explained Mr. Perlman, who, as a kid, liked to sketch blueprints of imaginary buildings.

His radicalization came in the summer of 2005. “I was passing by the Trylon Theater,” he said, referring to the famous centerpiece of the 1939 World’s Fair, located at 98-81 Queens Boulevard, “when I noticed construction workers taking jackhammers to its mosaic tiles.”

“What happened there was a real shame,” recalled Simeon Bankoff, executive director of the Historic Districts Council, who assisted Mr. Perlman in a failed effort to stop the Trylon’s decimation. “It was a beautiful building and one of those things that could have been reused. … But Michael is indefatigable and went on to other things.”

Not all of his efforts have been as successful as his diner-relocation deals. His campaign last fall to save the Playpen Theater at 693 Eighth Avenue, for instance, failed to sway developer Daniel Tishman from demolishing the old vaudeville palace-turned-porn shop to make way for a new hotel building. “They weren’t willing to work with us,” Mr. Perlman said.

But that defeat only made the more recent success all the sweeter.

Over e-mail on Monday, Mr. Perlman seemed particularly pleased with the kind of people taking over the Cheyenne Diner.

“Father and son have thankfully restored various historic sites in Red Hook, and I’m proud they’re part of its future,” he said. “Mike plans on restoring the diner to its ’40 splendor, and I feel it will be great once he polishes up that gem, and patrons can experience the Cheyenne as it was initially conceived. … The counter and stools will likely be restored to its full length, since it was cut when a stove was installed midway. The paint may be stripped from the porcelain barrel ceiling, and the floor might be uncovered, revealing the original terrazzo or mosaic tiles, which were frequently used back then.”

He planned to reach out to former diner manufacturer Paramount Modular Concepts in Oakland, N.J., which now specializes in restoring old diners.

“I am hoping they will have blueprints and historic photos on file, which would assist us in the process,” he said.

“I may be getting a bit ahead of myself,” he added, “but you can see how enthusiastic I’ve become.”