Boris Johnson won the Conservative Party’s leadership election on Tuesday and will take the reins of the government Wednesday, fulfilling his decades-old ambition to become Britain’s Prime Minister.

As supporters compare his brash public persona to a modern-day Winston Churchill while his detractors liken him more to President Trump, the 55-year-old former mayor of London will have to demonstrate his ability to guide the country through the greatest test since the end of World War II.

Johnson, an avid supporter of Brexit, will attempt to succeed where outgoing Prime Minister Theresa May failed – getting Britain to honor the 2016 referendum result and leave the European Union. In addition to that, a crisis with Iran and a relationship with the U.S. in need of repair await him.

BORIS JOHNSON TO BECOME NEXT BRITISH PRIME MINISTER, AFTER WINNING CONSERVATIVE PARTY LEADERSHIP BALLOT

In this Friday, June 25, 2010 file photo, Mayor of London Boris Johnson, center, poses for photographers as he plays a game of table tennis with pupils in London. (AP Photo/Akira Suemori, File)

While he once joked that him becoming Britain’s prime minister was as likely as finding Elvis on Mars, his somewhat controversial and colorful public life has made him one of the most popular and recognized politicians in the country, with many believing he’s capable of a successful premiership.

He campaigned during the leadership election on getting Britain out of the EU on the scheduled date of Oct. 31 — with or without a deal, a promise that won over supporters of Brexit but created animosity with more moderate Conservatives who fear the consequences of a no-deal Brexit that experts say would plunge the country into recession.

Johnson was born in New York in 1964 and lived there until he was five years old. His ancestors include Turkish journalist and government minister Ali Kemal, one of Johnson’s great-grandfathers.

In this Thursday, June 21, 2018 file photo Britain's Foreign Secretary Boris Johnson talks to a British armed forces serviceman based in Orzysz, in northeastern Poland, during a ceremony at the Tomb of the Unknown Soldier and following talks on security with his Polish counterpart Jacek Czaputowicz in Warsaw, Poland. Boris Johnson aspires to be a modern-day Winston Churchill. Critics fear he's a British Donald Trump.  (AP Photo/Czarek Sokolowski, File)

He had a dual British-American citizenship until 2016 when he renounced it, signaling his ambitions to become the prime minister, but also sidestepping potential tax responsibilities across the Atlantic.

Back in 2014, he reportedly said the U.S. government was trying to tax the sale of his home in London, calling it “absolutely outrageous.” He later paid the tax bill after the IRS sent an official demand.

Following his education at the elite boarding school Eton College and Oxford University, Johnson went to work as a journalist, including Brussels correspondent for the Daily Telegraph where he often reported on the EU’s regulation of Britain.

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Then came his political career, first as a Member of Parliament, later as the mayor of London. The victory in London, a stunning feat given the traditional left-wing grip on politics in the capital, cemented his credentials of being able to appeal to voters across the board rather than just Conservatives.

Mayor of London Boris Johnson got stuck on a zip-line during BT London Live in Victoria Park on August 01, 2012 in London, England. (Getty)

His reign as the mayor prompted mixed reviews. He was instrumental in the successful 2012 London Olympics, an example Johnson’s supporters cite to show his ability to handle complex governance issues. But the event also showcased his ability for gaffes, including a now-infamous scene of him getting stuck on a zip wire mid-air as he waved Union Jacks.

Critics, meanwhile, say he backed vanity projects that include a little-used cable car, an unrealized “Boris Island” airport and a never-built “garden bridge” over the River Thames. A bicycle-sharing scheme dubbed “Boris bikes,” which share his name, was actually spearheaded first by the previous mayor.

As he rose to prominence, he also made a number of comments deemed offensive by critics, including saying Papua New Guineans were cannibals, former President Barack Obama had a dislike of Britain due to his “part-Kenyan” ancestry, and just last year compared Muslim women who wear full-face veils to “letterboxes.”

In this Oct. 15, 2015 file photo, Boris Johnson takes part in a Street Rugby tournament in a Tokyo street, wiping out a Japanese school boy in the process (Stefan Rousseau/PA via AP)

Earlier this year, he said police funding was being “spaffed up the wall” by investigating allegations of historic abuse, adding that an “awful lot of police time” is being wasted by looking at “historic offences and all this malarkey.”

He also raised eyebrows at the Beijing Olympics in 2008 after saying that table tennis, contrary to claims that it was invented in China, was actually an English creation from the 19th century and was called whiff-whaff.

Despite his prowess for gaffes, Johnson played a key role in the EU referendum in 2016, joining the campaign to leave the EU. He shortly became the face of the winning campaign.

Shortly after the referendum, then-Prime Minister David Cameron resigned, prompting Johnson to jump in the race to succeed him – but his bid abruptly ended after one of his closest allies, Michael Gove, decided to run against him.

May, who instead became the premier despite her voting to remain in the EU, extended an olive branch to Johnson and made him the foreign secretary, where his two-year stint was riddled with numerous controversies, especially after saying that a violence-torn Libyan city could become a tourism hub once authorities “clear the dead bodies away.”

FILE - In this Friday June 24, 2016 file photo Vote Leave campaigners Michael Gove, left, leaves the lectern as Boris Johnson applauds at a press conference at Vote Leave headquarters in London. (Stefan Rousseau/Pool via AP)

He resigned in 2018 over his opposition to May’s Brexit blueprint, arguing it would make Britain a “colony” of the EU.

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While Johnson’s public life provides plenty of ammunition for his critics, some have also pointed out to his raucous private life and a history of affairs.

He announced back in September that he was divorcing his second wife, Marina Wheeler, after 25 years of marriage that produced four children. Johnson has fathered at least one other child outside his marriage.

Last month, amid the heat of the leadership race, police were called by neighbors after hearing a loud argument between Johnson and his girlfriend, Carrie Symonds.

The Associated Press contributed to this report.