Donald Trump has appointed Breitbart News' Steve Bannon to be chief executive of his presidential campaign, and those familiar with the conservative media mogul's style claim he is ready to win the White House race "at all costs."

Bannon, a Harvard graduate, ex-Goldman Sachs banker and former naval officer, is taking a temporary leave of absence from to preside over the Republican presidential nominee's political team for the remainder of his campaign against Hillary Clinton.

The move, announced Wednesday morning, was unsurprising to Republican operatives and reporters who claim Breitbart has morphed into a propaganda machine for the GOP nominee, or an "unaffiliated media super PAC for the Trump campaign," as one outgoing employee said in mid-March.

So who is Steve Bannon and what will he do to transform candidate Trump and his campaign into an election-winning machine between now and Nov. 8?

He's a 'dangerous' man in politics

In the hours after Bannon's hiring was announced, the Breitbart executive was described as a "bare-knuckle brawler," "huge piece of manpower" and "messaging machine." Ten months ago, Bloomberg News dubbed him "the most dangerous political operative in America."

Bannon, a proponent of right-wing populism, developed a mission at the beginning of the 2016 election cycle: see to it that neither the Democrats' or Republicans' odds-on favorite makes it to the White House. And so led the crusade against GOP stalwarts like Marco Rubio and Jeb Bush, feeding off voters' anti-establishment mood and propping up Trump in order to sink their campaigns.

Presumably, Bannon now feels it is Clinton's turn to face a takedown. The question is how far will he go without permanently severing Trump's already-shaky relationship with Republican leaders, to make it happen.

"Steve's job is going to be to keep the populist grassroots fired up and keep the pressure on Clinton," veteran GOP strategist Ford O'Connell told the Washington Examiner.

But if Bannon is as dangerous as he's professed to be, the Trump campaign could soon become even more unconventional.

He's financed and helped produce a number of films

Not only does Bannon's resume include two Ivy League degrees and a military background, the conservative filmmaker has been a producer and director of several political documentaries.

In 2004, he helped direct "In the Face of Evil: Reagan's War in Word and Deed," an exploration of the Cold War and Ronald Reagan's role in the collapse of the Soviet Union. In 2010, two years into Obama's presidency, Bannon produced a film that documented Democratic voters' disappointment with the administration's failure to deliver "the hope and the change."

He went on to direct additional films about the unsustainable federal debt ("Generation Zero," 2010), former GOP vice presidential nominee Sarah Palin ("The Undefeated," 2011) and the Occupy Wall Street movement ("Occupy Unmasked," 2012).

His latest film, "Clinton Cash," debuted at the Cannes Film Festival in April and is based on the 2015 New York Times bestseller, Clinton Cash: The Untold Story of How and Why Foreign Governments and Businesses Helped Make Bill and Hillary Rich, by conservative author Peter Schweizer.

The subject of the film — Clinton's questionable relationship with foreign governments and donors to her charitable foundation — recently resurfaced amid new revelations about the Clinton Foundation's influence on the State Department.

Bannon's background in multimedia and foray into filmmaking means he could help Trump create his own cable empire, a venture floated by sources close to candidate in a June article by Vanity Fair, or other new media platform if the billionaire businessman fails to become commander in chief.

He's already stirring up trouble in conservative circles

While many Trump supporters have lauded the candidate for bringing on Bannon as the campaign's CEO, a number of conservative figures and political professionals are already worried that he was hired.

"I have shelved so many hot takes this morning I can't even tell you," Brendan Buck, the communications director for House Speaker Paul Ryan, tweeted Wednesday morning. Ryan has routinely been chastised by, with headlines describing him as "the reason the GOP is losing America" and someone who "sucks up to anti-Trump fat cats."

Stuart Stevens, the lead political strategist for Mitt Romney's presidential campaign, appeared to shudder at the idea of Bannon joining Trump for classified intelligence briefings, and suggested that voter data gathered by the Republican National Committee could soon be "used by Breitbart."

Prominent conservative activist Ben Shapiro, a former editor-at-large for Breitbart who ditched the site in March, asked voters to "imagine one of the worst people you personally know running the Republican nominee's campaign."

"That's my life this morning," he tweeted shortly before describing Bannon as "a legitimately sinister figure" in a lengthy column about his hiring.

Kurt Bardella, another ex-Breitbart employee, told the Examiner that Bannon's hiring should send a signal to the RNC that it's time to "pull its resources from the Trump campaign."

"For anyone who thought that the campaign was combative and challenging to this point, it's going to be that times 10 going forward," Bardella said, adding that his former boss has a tendency "to make profanity-laced phone calls at people" and employ "tactics of intimidation and bullying."

One person, however, was particularly happy to see Trump bring Bannon on board.

Clinton's campaign manager, Robby Mook, celebrated the announcement, claiming the Breitbart executive's appointment signals that Trump has "decided to double down on his most small, nasty, divisive instincts."

Sarah Westwood contributed to this report.