Rudy Giuliani’s passport filled up quickly in late 2018.

That October, he traveled to Armenia to headline a pro-Russia conference where he met with the country’s acting defense minister. In November, Giuliani flew to Uruguay to discuss a security plan with President Tabaré Vázquez. And in December, he journeyed to Bahrain and had a one-on-one meeting with King Hamad Bin Isa al-Khalifa in the royal palace.

The trips were not out of the ordinary for Giuliani, the former New York City mayor-turned-personal lawyer to President Donald Trump.

Over the past 18 months, he’s done consulting work and delivered paid speeches for an array of foreign clients while also representing the president, an arrangement that has sparked criticism from government ethics experts and forced Giuliani into awkward exchanges with overseas reporters.

“I am not here in my capacity as a private lawyer to President Trump,” Giuliani told local reporters during his Armenia trip when pressed on the U.S.’s stance on the Armenian genocide, according to the country’s state-run news agency. “I am here as a private citizen.”

Giuliani’s overseas work began in the early 2000s when the well-known former federal prosecutor launched a security consulting firm. But it has attracted fresh scrutiny after it was revealed that he was leading the effort to pressure Ukrainian officials to dig up dirt on Joe Biden, Trump’s chief political opponent. Democrats and some diplomats have accused Giuliani of running a “shadow foreign policy” on behalf of the president, an allegation at the center of the impeachment inquiry roiling Washington.

An NBC News review of Giuliani’s international dealings — based on a search of government lobbying filings, company releases, social media posts and international press accounts — reveals contracts and meetings with a voluminous roster of overseas clients that over time have prompted questions about whom he represents and whether his role as Trump's private lawyer has sent confusing messages to foreign governments.

Among his clients past and present: A Brazilian state bordering the Amazon jungle. A Russia-leaning Ukrainian mayor. A heavyweight boxing champion-turned-Ukrainian mayor. The government of Qatar. The government of Gabon. A Peruvian presidential candidate accused of campaign finance violations. A Romanian businessman accused of real estate fraud. A Turkish gold trader accused of laundering Iranian money. An Argentinian senator. A Chilean president. An Iranian dissident group once designated by the U.S. as a foreign terrorist organization.

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Giuliani’s early overseas business dealings were largely straightforward: security consulting in places like Honduras, Panama and Colombia. But his more recent international activities, in Eastern Europe in particular, reflect what appears to be a blurring of the lines between Giuliani the consultant and Giuliani the influential voice in the ear of the president, experts say.

“We don’t know what role Giuliani is playing,” said Scott Amey, general counsel for the non-partisan Project on Government Oversight. “To operate as a personal attorney to the president, have private business dealings and operate as a quasi-government employee is a mixture that is inappropriate and shouldn’t be happening.”

Amey noted that Giuliani isn’t subject to the conflict of ethics rules that govern the conduct of official employees of the federal government.

“He blurs the line between what role he’s playing so much, without any rules, that it really calls into question who he’s working for and whose interests he’s trying to represent,” Amey said.

Giuliani did not return requests for comment.

He launched his security and management consulting firm, Giuliani Partners, soon after his second term as New York City mayor came to an end in late 2001.

Giuliani was riding high at the time. His leadership in the aftermath of the 9/11 attacks turned him into a national hero and earned him the nickname “America’s Mayor.”

Clients flocked to his consulting firm. Paid speaking gigs piled up. Money flowed.

Leveraging his reputation as a hard-nosed federal prosecutor and crime-busting mayor into a career as a high-priced expert on security and management turned Giuliani into a multimillionaire.

Between January 2006 and February 2007, he hauled in $11.4 million from speaking engagements and at least $6 million from his consulting work and other activities, according to financial disclosure forms he filed ahead of his failed 2008 presidential bid.

Many of his consulting firm’s early clients were American-based companies. Some of the relationships still generated unflattering headlines.

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Purdue Pharma, the OxyContin maker now accused of fueling the nation’s opioid epidemic, hired Giuliani Partners in May 2002 when it was under investigation by the DEA and FDA, the firm announced at the time. Giuliani’s firm also courted controversy when it agreed to a contract with a Florida company run by a close Giuliani friend, Hank Asher, who admitted to working as a 1980s-era cocaine smuggler but was never charged.

The Giuliani name had cache across the globe. His firm also attracted significant business overseas, especially in Latin America.

He provided consulting work in Mexico, Brazil, Panama, Guatemala and El Salvador.

But as he got closer to President Trump, his overseas activities grew more complex and more contentious.

The Romanian real estate tycoon

Even before his deals in the Ukraine generated controversy, Giuliani’s conduct related to Romania rankled U.S. officials.

Gabriel “Puiu” Popoviciu, a wealthy Romanian real estate tycoon, assembled a high-profile legal team in 2016 when he was facing the prospect of prison time on charges of orchestrating a corrupt land deal.

Popoviciu enlisted the services of former FBI director Louis Freeh, who quietly tapped Giuliani in the effort.

The prosecution of Popoviciu came amid a crackdown on corruption in Romania, a development that was welcomed by U.S. officials. But in August 2018, Giuliani wrote a letter to Romania’s president and prime minister in which he criticized as overly excessive the country’s efforts to rein in graft.

The missive from the American president’s personal lawyer was seen as a boost for Popoviciu. But in contradicting the U.S. stance on anti-corruption efforts, Giuliani’s letter dismayed U.S. diplomats on the ground and sowed doubts among Romanian officials about exactly what Washington was advocating, said Michael Guest, a former U.S. ambassador to Romania.

“His letter muddied U.S. foreign policy interests,” Guest said.

Giuliani blurred the line between his role as the president’s lawyer and his private consultant work, Guest said, by failing to disclose which client paid him to write the letter.

The Romanians were “put in a difficult position, and a confusing position,” Guest said. “Giuliani shouldn’t have sent the letter, and he should be ashamed that he sent the letter.”

Popoviciu, meanwhile, was convicted and sentenced to seven years in prison.

The Turkish gold trader

Giuliani was named Trump’s cybersecurity adviser in January 2017. One month later, he and his former law partner Michael Mukasey traveled to Turkey to meet with President Recep Tayyip Erdogan.

The pair made the trip on behalf of Reza Zarrab, a Turkish gold trader charged in a multimillion dollar scheme to evade Iranian sanctions. The purpose: to seek a “state-to-state resolution of the case,” Mukasey said in a court filing.

The trip prompted the New York federal prosecutors who brought the case to complain to the judge about what appeared to be a secret extrajudicial effort by Giuliani and Mukasey to clear Zarrab of criminal charges in the U.S.

Giuliani was pushing for a prisoner swap with Turkey and urged Trump to help in the effort, according to The New York Times.

"Mr. Giuliani and Mr. Mukasey's involvement in this case is intended to occur entirely outside of the Court's purview and knowledge,” then-acting U.S. Attorney Joon Kim wrote to the judge in March 2017.

The court compelled Giuliani and Mukasey, who had not informed the court about their representation of Zarrab, to explain their roles in his case.

In an affidavit, Giuliani wrote that he had been retained to “provide advice and to consult, but not appear in court, in the defense of Mr. Zarrab.”

“Those services have focused principally although not exclusively on an effort to determine whether this case can be resolved as part of some agreement between the United States and Turkey that will promote the national security interests of the United States and redound to the benefit of Mr. Zarrab.”

Giuliani’s efforts proved unsuccessful. Zarrab ultimately pleaded guilty and cooperated with federal investigators.

But Giuliani’s role in the affair, which has come under renewed scrutiny, may have run afoul of the Foreign Agents Registration Act, or FARA, legal experts say.

The law requires Americans to disclose to the Justice Department any lobbying or public relations work on behalf of a foreign entity.

Turkey is not the only example where experts say Giuliani may have engaged in illegal lobbying.

The Ukrainian boxing champion

Giuliani’s connection to Ukraine dates back more than a decade. In May 2008, his firm, Giuliani Partners, announced that it was advising the campaign of Vitali Klitschko, a former boxing champion running for the mayor the Ukrainian capital city of Kyiv.

In an unusual spectacle, the former mayor held a Times Square press conference to trumpet his support for a candidate seeking office in a city an ocean away.

“They need a leader like you, who can deal with corruption, who can deal with reform of government, which is so necessary,” Giuliani said, according to news accounts at the time.

Vitali Klitschko, former heavyweight boxing champion and Ukrainian politician, speaks to the media while walking through Dublin on March 6, 2014. Peter Morrison / AP file

Giuliani’s endorsement didn’t have the intended effect. Klitschko lost the election but he secured victory six years later and remains in office.

Giuliani was tapped to be President-elect Trump’s informal security adviser in January 2017. Six months later, he traveled to Ukraine at the invitation of Victor Pinchuk, a Ukrainian oligarch who had donated $150,000 to Trump’s now-defunct foundation in 2015.

Giuliani delivered a speech to an audience of more than 600 Ukrainians, highlighting the need to root out corruption. "To have a rule of law means to have honest police, honest prosecutors, honest judges, and honest political leaders,” Giuliani said, according to a release from the Victor Pinchuk foundation.

Later in his talk, Giuliani addressed Russia’s annexation of Crimea. “I believe that Eastern Ukraine has to be returned to Ukraine and that has to be an objective of not just U.S. but of western foreign policy. The invasion was illegal.”

On that same day in June 2017, according to Pinchuk's foundation, Giuliani met with a host of top Ukrainian political figures, including President Petro Poroshenko, Prime Minister Volodymyr Groysman and Klitschko.

Giuliani also met with someone else, a man who’s now at the heart of the impeachment inquiry: Yuriy Lutsenko, the country’s then-prosecutor general.

Lutsenko is now alleged to have worked with Giuliani in forcing out Ukraine’s U.S. ambassador and seeking damaging information about Biden and his son Hunter, who worked for a Ukrainian gas company.

Long before the scandal erupted, Giuliani returned to Ukraine again, just a few months after his meeting with the group of powerful Ukrainian politicians. In November 2017. Giuliani visited the city of Kharkiv in a trip reportedly orchestrated by Pavel Fuks, a Ukrainian oligarch who negotiated with Trump in the 2000s to build a Trump Tower Moscow.

Fuchs hired one of Giuliani’s firms, Giuliani Security & Safety, to help city officials devise a security and emergency plan and to offer advice on a planned Holocaust memorial, Giuliani told Mother Jones magazine.

“Giuliani’s company provides lobbying services, and they are very strong in security,” Fuchs told Bloomberg News earlier this year. “He’s a star.”

That Fuchs viewed Giuliani as a lobbyist and said so publicly alarmed some FARA experts.

“They thought of him as being their lobbyist. I think that’s a problem right there,” said Bill Marshall, a professor of law at the University of North Carolina and a former deputy White House counsel and deputy assistant to the president under the Clinton administration.

On the same November 2017 trip to Ukraine, Giuliani met once again with President Poroshenko and the two discussed “ways to overcome Russian aggression and the course of reforms in Ukraine,” according to an account by the Interfax News Agency.

It would emerge two years later, after Poroshenko lost the election, that he and his chief prosecutor appeared to be open to Giuliani’s agenda of pushing for an investigation that would ensnare the Bidens. The new president, Volodymyr Zelenskiy, was the other man on the now-infamous Trump call that fueled the launch of the impeachment inquiry.

“Rudy very much knows what’s happening, and he’s a very capable guy,” Trump told Zelenskiy at one point in the call, according to White House notes of the call. “If you could speak to him, that would be great.”

One month later, in August 2019, Giuliani flew to Madrid to meet with Andriy Yermak, a top Zelenskiy aide.

Mixed reactions in Latin America

The fallout in the Ukraine has focused attention on Giuliani’s long history of courting overseas clients.

Over the past two decades, his international security consulting has garnered mixed reviews in the places that hired him.

Giuliani’s security plan for the Brazilian state of Amazonas drew raves from Gov. Amazonino Mendes, who has pushed for clearing out the Amazon jungle and promised a chainsaw to constituents as part of the effort.

"He's a magician," Mendes said in a video posted to social media after he received a preliminary version of Giuliani's crime-fighting plan in June 2018.

But the $1.4 million contract between Amazonas and Giuliani Security & Safety later touched off controversy. State prosecutors ultimately launched an investigation into “any irregularities” in the hiring of Giuliani’s firm, according to a local media report. It’s unclear what came of the probe.

The security proposal Giuliani’s firm developed for in 2003 for Mexico City — at a reported price of $4.3 million — also triggered a public backlash. “The Giuliani plan did not have any effect,” police officer Nicocio Acosta Leon said a the time, according to the New York Sun. “It was money in the trash really.”

One of Giuliani’s longest running paid relationships belongs to a fringe Iranian group accused of killing six Americans in the 1970s. Giuliani has been delivering paid speeches and meeting with representatives of the Mujahedeen e-Khalq (MEK) since at least 2010, he previously told NBC News.

The dissident group launched attacks against Americans and the Iranian government 40 years ago, but it now fashions itself a democratic-minded group focused on toppling the country’s autocratic leaders.

Giuliani’s work for the MEK and his other clients has been hugely profitable. He earned $7.9 million in 2016 and $9.5 million in 2017, according to the divorce lawyers representing his third ex-wife.

Andrew Kirtzman, a longtime New York City journalist who wrote a biography of Giuliani, said he believes the pivotal moment in the evolution of Rudy Giuliani was his failed presidential run in 2008.

“Giuliani was wearing the 9/11 halo and was a bonafide hero,” said Kirtzman, author of “Rudy Giuliani: Emperor of the City.” “And the election was a debacle, a total debacle.”

After starting off as the GOP front-runner, Giuliani suffered a spectacular collapse culminating in him dropping out of the race after the Florida primary, having failed to notch a single primary victory.

“The luster was gone after the campaign, and that’s when I think he started focusing on making money and his choices of clients were questionable,” Kirtzman said.

For Kirtzman, Giuliani’s embrace of Trump and willingness to act as his personal fixer is hardly surprising.

Giuliani has always craved the spotlight. Trump provided him with a path.

“He has spent most of his adult life famous and Donald Trump represented a vehicle to get back into the game,” Kirtzman said. “And Rudy Giuliani has never done anything halfway.”