Ms. Le Pen, in America at his invitation, he said, had suggested a coffee in the lobby of Mr. Trump’s building, where he conceded, “there was always a remote possibility” of seeing the then president-elect. “I said, ‘Listen, Marine, you know there is all the media there,’” Mr. Lombardi recalled, saying Ms. Le Pen insisted no one would recognize her. “And sure enough: Bang.” (A spokesman for Ms. Le Pen did not return a call for comment.)

Born in Geneva, Mr. Lombardi has also introduced himself as Count de Canevaro and wears a gold ring bearing his family’s coat of arms. In the library at Mar-a-Lago he walked from a painting of Mr. Trump in tennis whites to a 1750 oil painting of Benedetto Saluzzo Della Manta, who he claimed came from the same region as a distant ancestor.

He moved as a child to Rome, where he said the riots of 1968 and the rampant communism of his university classmates prompted his departure to America. He arrived in his 20s, bummed around, married, had children, started a jewelry business, broke into real estate, divorced and met Gianna Lahainer at a National Italian American Foundation event.

Ms. Lahainer, a former office worker from Trieste who had married the real estate mogul Frank Lahainer, was already a friend and neighbor of Mr. Trump, having bought one of the first condos in Trump Tower. When Mr. Trump first considered buying Mar-a-Lago in 1985, she warned him about the noise pollution from plane traffic over the estate, prompting him to renegotiate the price.

Mr. Lahainer died in 1995 and in 2000, his widow, then 65, married Mr. Lombardi. The couple delighted in telling how she put her late husband on ice at a funeral home because she did not want to miss the social season. “Why should I wait?” she once told the Palm Beach chronicler Ronald Kessler.

Mr. Lombardi said that in reality his wife could not immediately procure permits to send her husband’s body back to his Italian birthplace, but the story amounted to “good advertising.”

While his second wife introduced him to Mr. Trump’s Mar-a-Lago circle, Mr. Lombardi acted as an unofficial (“always unofficial”) representative in the United States of Italy’s anti-immigrant Northern League, often called The Lega in Italy. He said he first met Ms. Le Pen in the early 1990s in Brussels through a friend in the European Parliament.