Kimberly Guilfoyle was a long way from Mar-a-Lago.

The U.S. ambassador to Greece-Donald Trump Jr. former fiancée-was shuttling back and forth to Bulgaria's capital on a mission this spring. The Trump administration wanted allies on Europe's eastern edge to buy billions of dollars of American natural gas.

There was just one thing.

The Bulgarian government, she told people, should deal with a Greek construction firm called Aktor Group, a newcomer to the gas business that had teamed up with a Greek state-backed energy company to bring in liquefied natural gas from the U.S. "There is no doubt that this is kind of an official position of the U.S. government," said a person familiar with the talks.

Sitting beside the 57-year-old ambassador in an audience with the Bulgarian president was a 39-year-old named Christos Marafatsos. He has attended so many of her meetings that some foreign officials mistook him for her chief of staff. In fact, he is a top lobbyist for Aktor, whose CEO had flown Guilfoyle to the country on a private jet.

A one-time prosecutor who morphed into a MAGA icon, Guilfoyle is parlaying her ambassadorship to Greece into one of the Trump administration's most important diplomatic roles. The former Fox News host has crisscrossed the Balkans to help Europe wean itself from Russian energy, via a "vertical gas corridor" meant to receive U.S. LNG in Greece and pipe it toward Ukraine.

But she has puzzled government officials across the region with her persistent promotion of a specific Greek company-and her extensive efforts to involve Marafatsos, a neophyte in both diplomacy and energy.

His prior experience includes co-founding a Washington, D.C.-area produce distributor and working in businesses ranging from real-estate consulting to creating "the ultimate immersive experience" of the Acropolis in IMAX 3-D.

These days, the Maryland-raised Marafatsos is frequently seen at Guilfoyle's side, acting as her unofficial gatekeeper and joining her for meetings at her ambassadorial residence and with government officials in countries around the region-a highly unusual move for a private citizen.

Several people who have met with Marafatsos and the ambassador-including government officials-said he made no mention of his ties to Aktor.

At a conference earlier this month in Thessaloniki, Greece, where officials from nine countries gathered to discuss their progress on the vertical corridor, a Wall Street Journal reporter waiting outside watched Marafatsos and Guilfoyle arrive in the back of a black BMW at the head of the U.S. convoy. Marafatsos entered the city's MET Hotel through a separate entrance, away from photographers.

U.S. Embassy staffers who spent years pushing for the vertical gas corridor never met with Aktor executives or even heard the name raised as a potential partner, according to former State Department officials who dealt closely with the matter.

Robin Brooks, a 21-year foreign service officer who served as National Security Council director for the Balkans and Central Europe during the Biden administration, said that a U.S. ambassador promoting a foreign company is "absolutely problematic." Bringing a registered lobbyist to meetings with foreign officials, she said, "calls into question whether the meeting is advancing American interests or advancing some sort of private interest."

A U.S. Embassy official said the ambassador traveled to Bulgaria "to advance American interests: increasing sales of U.S. LNG to European partners and decreasing European dependence on Russian gas." He said she was in "full compliance with State Department guidance" on official travel.

Jesse Binnall, a lawyer for Guilfoyle, said she has "worked with companies across the energy sector" and hasn't been focused on one company. He said her official meetings are coordinated through embassy channels, not through Marafatsos.

Secretary of State Marco Rubio, in a statement provided by the White House, called Guilfoyle an "incredibly effective advocate for the President's agenda." He said he and Trump "greatly value" her work.

Marafatsos said in a statement: "I am proud to champion commercial initiatives that advance U.S. interests and create lasting economic opportunity in Greece and Southeastern Europe. I am grateful for the opportunity to draw on my business experience and leadership in the Greek American community." His lawyer disputed some of the Journal's reporting but declined to elaborate.

In a letter, lawyers for Aktor said Guilfoyle wasn't improperly promoting Aktor's commercial interests and that the company's involvement in the vertical corridor preceded "any contacts" with the ambassador. The lawyers said Aktor is an "attractive candidate for furthering U.S. goals and interests" because it has no ties to Russian gas, unlike some of its Greek competitors.

Guilfoyle wields outsize influence across a part of Europe that has been clamoring for closer ties to the Trump administration. The region had only one confirmed ambassador across 10 countries when Guilfoyle arrived in Athens last fall, part of a pattern of widespread diplomatic vacancies that has dramatically empowered the handful of envoys abroad seen as close to Trump.

In November, Aktor announced a joint venture, Atlantic-SEE LNG, that would be split 60-40 between it and DEPA, a Greek state-backed energy company. In the months since, Aktor and its joint venture have signed memorandums of understanding and commercial agreements with gas companies in Bulgaria, Ukraine, Bosnia and Herzegovina and Romania. A $6 billion deal Guilfoyle helped Aktor secure in Albania would, if completed, have the country buy gas from the company through 2050.

It is unclear whether all the deals will come to fruition. On Friday, Ukraine's state-owned gas company told the Journal negotiations have halted over future purchases from Atlantic-SEE.

Ambassador's odyssey

Guilfoyle has become a potent symbol of the new school of American diplomacy under Trump: its fusing of celebrity, business, and geopolitics.

Guilfoyle, who was once married to California Gov. Gavin Newsom, speaks of her strong connections to the Trump family and broadcasts videos to nearly two million Instagram followers, interspersing meetings with regional leaders with visits to European fashion shows and art galas, decked in crystal-adorned dresses.

She is friends with Greek pop star Konstantinos Argiros, who at a recent concert spotted her in the crowd chatting with Marafatsos and twirled her around to one of his hit songs. Jefferson House, the official ambassadorial residence where she often takes meetings, has been decorated with large black-and-white portraits of Guilfoyle, according to people who have visited.

Some Greek officials say they are happy their country, often overlooked in Washington, has the attention of an ambassador who can easily reach the U.S. president.

They are also fearful of getting on her bad side. In March, at a dinner in Athens attended by Greek and U.S. officials, Guilfoyle got into an argument with Greece's energy minister, Stavros Papastavrou, in front of the other guests. Referring to the impending collapse of the Romanian government, Guilfoyle told the group, "We can do that to any country we want. We can do that here," according to a person who attended the dinner and others who were told about it. The conversation became heated, with Papastavrou retorting that the U.S. couldn't replace the government of Greece, which was elected by the people. Guilfoyle's lawyer disputed the characterization of the exchange.

Guilfoyle's diplomatic appointment came in the throes of a high-profile breakup.

She began dating Trump Jr. halfway through his father's first term and quickly emerged as one of Trump's most aggressive defenders. In her 2020 convention speech, she warned that Democrats were trying to enslave Americans with liberal ideology.

The couple got engaged before Trump left office, and that spring they bought a $9.7 million Florida mansion. Guilfoyle pursued a series of business ventures-a line of hair care and fragrances called Flor de Maga; champagne ventures with names such as 1776 Liberté and Liberty Dream; a pet pharmaceuticals service called PETriot Vet, according to U.S. Patent and Trademark Office records. Those trademarks have since been abandoned.

Then she hit the campaign trail for Trump's re-election, urging the crowd at the Republican convention in 2024 to "rise up" on his behalf. That summer, photos began to emerge of Trump Jr. with 39-year-old Palm Beach socialite Bettina Anderson. Trump, who had been fond of Guilfoyle, took to social media in December with surprising news: He was naming her ambassador to Greece.

Her appointment followed behind-the-scenes lobbying by people close to Trump Jr., who supported giving Guilfoyle the job, according to people familiar with the discussions. Guilfoyle had spent weeks calling people around her former fiancé asking how the two could reunite, some of whom began to float the idea of various ambassadorships.

Guilfoyle had long been drawn to Greece: She told friends she liked the country's relevance on the world stage and its glamorous vibe-citing Jacqueline Kennedy Onassis, the former first lady who married a Greek shipping tycoon after her husband's assassination. The U.S. Embassy official said the ambassador honeymooned in Greece and has spoken about her love for the country ever since she studied Greco-Roman history in college.

Greek news outlets quickly dredged up additional remarks, noting that Guilfoyle, as a Fox News co-host during Europe's debt crisis in 2015, had said Greeks needed to be trained like when a "dog pees on the rug."

"It doesn't matter if you make great yogurt," she said. "I don't care."