A couple of weekends ago, Paolo Zampolli received a text message from Melania Trump, the wife of the Republican candidate for president, urging him to give her a call. The next day, Mr. Zampolli, a former modeling agent who had discovered the Slovenian 20 years ago in Milan, listened as Ms. Trump expressed anguish over a gossipy report in the British tabloid the Daily Mail accusing her and Mr. Zampolli of operating an escort service in the 1990s.
“This is outrageous,’” Ms. Trump said on the call, according to Mr. Zampolli, explaining that she was considering filing a suit against the Daily Mail for making false and defamatory statements. He said she sounded “extremely disturbed.”
Mr. Zampolli, 46, sounded less than disturbed as he spoke over a recent lunch of pasta in his Gramercy Park townhouse, which is decorated with works by Canaletto, de Chirico and Picasso. In his monogrammed dress shirt and Italian-accented English, the onetime mainstay of New York gossip pages called the report “rubbish” and “disgusting,” but also seemed to relish his return to the public eye.
He spoke emphatically about his central role in an article earlier this month exploring Ms. Trump’s visa history (“reprinted in 550 publications around the world.”) and had lined up more interviews about the Daily Mail article later in the day.
By stepping back into the spotlight, Mr. Zampolli, a tireless self-promoter of mysterious means, brings into the 2016 presidential race an explicit reminder of the company the Trumps and Clintons kept in the behind-the-velvet-rope heyday of fin-de-20th-siècle New York. For two couples often accused of having an exceptionally transactional worldview, Mr. Zampolli is both Zelig and an open-collared emblem of the social waters in which they swam.
He secured Ms. Trump’s visa to the United States and introduced her to her future husband at a 1998 party he hosted at the Kit Kat Club. (Mr. Zampolli’s parties have featured an alligator, tiger cubs and models at nightclubs blowing kisses at Fashion Television cameras.)
He flew with Mr. Trump on his jet to attend the mogul’s wedding at Mar-a-Lago in Palm Beach, Fla. There, he said, “I was introduced to Hillary by Huma,” referring to Huma Abedin, whom he said he knew from events in New York.
By then, he said, he had already met Mr. Clinton “many, many, many” times. He called Mr. Clinton’s former adviser Doug Band “Dougie” and used to be close to Ronald Burkle, the billionaire investor who was once a close friend, private-jet provider and business partner of Mr. Clinton. (Mr. Clinton “was not coming to parties with me and the models,” Mr. Zampolli said.)
The Clinton campaign, Mr. Trump and Mr. Burkle declined to comment about Mr. Zampolli. But Ms. Trump wrote in a statement last Thursday: “I have known Paolo Zampolli since 1995 when we first met at a modeling agency in Milan. He loved my portfolio and encouraged me to expand my career to New York City. Paolo was a very professional agent and still remains a friend today. The defamatory statements reported by the Daily Mail are 100% false.”
These days, Mr. Zampolli has mostly traded in the fashion and real estate business for diplomatic pursuits. In 2013 he became, by decree, the United Nations ambassador of Dominica, a country of which he is not a citizen. A Brazilian model, Amanda Ungaro, his wife of a dozen years and the mother of his young son, herself became ambassador of Grenada to the United Nations, also by decree.
In his office, along with pictures of him posing with Mr. Clinton and Mr. Trump’s jet, there are hundreds of framed photographs of him with dignitaries. His passion now, he says, is sustaining the life aquatic. (“The ocean dies, we die.”)
He has started an organization, We Are the Oceans, the flags of which fly outside his house and whose scuba-themed pillows are on his oversize bed. In March, Page Six covered a gala of ambassadors and pouting socialites at his home that in part benefited an organization called Save Our Shark Coalition.
Asked how he broke into the diplomatic corps, Mr. Zampolli shrugged. “I have been always good to put people together and make things happen,” he said.
An only child, Mr. Zampolli was raised in a wealthy Milanese family. He said his grandmother was a cousin of Pope Paul VI and that he spent his summers deep-sea diving in the Mediterranean and his winters skiing in St. Moritz, Switzerland. His mother lives on the fifth floor, where she polishes silverware and tells a visitor she “would like to be proud of my son.”
He said his father owned Harbert, a toy company best known for introducing to Italy “Star Wars” figures and the Easy-Bake Oven (a.k.a. Dolce Forno.) His father died in a skiing accident when Mr. Zampolli was 18.
Handsome with slicked-back black hair, Mr. Zampolli left college to take over the toy company but considered Milan “too small.” He sold the company to Silvio Berlusconi, the Italian billionaire and eventual prime minister.
Mr. Zampolli had his eye on other amusements. In 1994, he organized the Look of the Year contest in Ibiza, Spain (“Sponsored by Replay Jeans,” he said, out of habit). He then became friendly with John Casablancas, the founder of Elite Model Management, who brought him to New York to work in the modeling business.
He rented an apartment in Union Square and met Mr. Trump, whose grandiosity he admired and who, like him, was a fixture on the city’s nightclub circuit. “We both have a common interest,” Mr. Zampolli said. “We both like beautiful things.”
Mr. Zampolli drank Diet Cokes with Mr. Trump, a teetotaler, in the exclusive upstairs area of the hot spot Moomba and joined him at other celebrity and model hangouts like Bowery Bar. He also traveled the world scouting talent for his agency and met Ms. Trump at a Milan casting call.
Mr. Zampolli recalled that he asked her, “Would you like to come to New York to try the market?” where, he explained, she could make more money. “I would be very interested,” he said she replied.
“She was a very beautiful girl with her head on her shoulders,” Mr. Zampolli said.
Mr. Zampolli said that he secured an H-1B visa for the eventual Ms. Trump, calling the process “very very easy to do.” She moved into the same Union Square apartment building where he had lived and became friends with his girlfriend, a Hungarian model named Edit Molnar.
Mr. Zampolli said the photographer of a nude photo shoot of Ms. Trump that surfaced last month on the front page of The New York Post had incorrectly dated the pictures 1995, which raised questions about whether she had worked in the United States before possessing a work visa. “I spoke to the lawyer that did the visa, my understanding is that she came in ’96,” he said, adding “I had nothing to do with the green card.”
In a subsequent email, he wrote: “If u write something about model taking picture w/ nothing on Yes this is part of the business is like An actor in movies that as an intimate scene …. I Am sure POTUS Regan or Governor Svarzeneger [sic] do have intimate scene in their movies.”
In 1998, Mr. Zampolli introduced the future couple, but it was not his lone stab at matchmaking. In 2006 Mr. Zampolli, then the president of ID Models, arranged a meeting between Mr. Burkle and a reporter from Page Six, the gossip page where Mr. Zampolli boasted that he and his models had appeared “close to 54 times” in one year.
Mr. Zampolli suggested to Mr. Burkle that a better relationship with the newspaper could improve his treatment. Among other items, Page Six infuriated Mr. Burkle by describing him as someone known for flying around on his Boeing 757 with models and considering buying a modeling agency that he would perhaps run with Mr. Clinton.
Mr. Zampolli organized the meeting. It didn’t go well, with Mr. Burkle ultimately alleging to the F.B.I. that the writer had tried to shake him down in return for better coverage.
Mr. Zampolli tread carefully on the subject of his relationship with Mr. Burkle and Mr. Clinton. Asked whether he had ever hung out with Mr. Clinton and Mr. Burkle at the same time, he initially said, “Maybe, I don’t recall that much,” before adding he had met Mr. Clinton “so many times it may be that Burkle was there.”
Mr. Zampolli was less reluctant to talk about Mr. Trump, whom he suggested he preferred as a presidential candidate. (“I am scared and we need borders in this country,” he said.)
In late 2004, Mr. Zampolli’s fortunes in the modeling business had faltered and he lost a public auction to buy Elite Model Management. After taking in a Victoria’s Secret fashion show, he squeezed into a small banquette at his favorite restaurant, Cipriani Downtown, where he often ate twice a day, with the Trumps and David Copperfield, the illusionist and one-time boyfriend of the supermodel Claudia Schiffer.
He had lost his top model, and Mr. Trump told him: “If you lose your supermodel, you go out of business. But if I lose my superintendent, I have a thousand looking for that job the next day.” He added that Mr. Trump told him: “Paolo, you are too good for the fashion industry. You should come work with me.”
He looked at Melania, who smiled.
Mr. Zampolli entered the real estate business as Mr. Trump’s director of international development. (“Ciao, Paolo! Donald’s Matchmaker Goes From Pin-Ups to Penthouses” a New York Observer headline read.)
He had some success, but he also found Mr. Trump to be a tough boss. And when Mr. Zampolli negotiated a deal to buy his dream home in Trump Park Avenue, Mr. Trump vetoed it, saying, “I need much more,” Mr. Zampolli said.
Mr. Zampolli said he soon left Mr. Trump because the developer stopped developing and “there wasn’t much to do because there was no inventory.” Instead, he started shuttling around clients in a Rolls-Royce and helicopters as the founder of Paramount Group. The company made headlines for using former models as brokers to sell luxury apartments.
Back then, Mr. Zampolli explained his thinking to CNBC. “The gorgeous ladies,” he said. “They meet the most rich and powerful people of the world, and some of them, they keep this connection.”