(CNN) Donald Trump's campaign is undergoing a major staff shake-up with less than three months to Election Day, adding two officials to top posts overseeing his struggling campaign and signaling a shift toward campaigning as a scorched earth outsider in order to win.

Trump has named Steve Bannon, the executive chairman of Breitbart News and a former investment banker, to the post of chief executive and promoted Kellyanne Conway, a senior adviser and pollster to his campaign, to the position of campaign manager, Conway confirmed to CNN early Wednesday morning.

The addition of Bannon -- known for his brass-knuckled demeanor and his website's sharp tone -- came hours after reports surfaced that Roger Ailes, the recently ousted head of Fox News, will begin to advise Trump as he prepares for the presidential debates. The influence of both men lays the groundwork for unleashing Trump this fall from the more traditional presidential candidate framework, which Campaign Chairman Paul Manafort's leadership was brought on to create.

Manafort, the campaign's chief strategist, will stay on in his campaign chairman role, Conway said.

"I look at it as an expansion of the team. Paul remains as chairman," Conway told CNN.

Manafort himself said it was an "exciting day for Team Trump" in an emailed memo to the campaign staff that was provided to CNN by a campaign source. He added that he will provide the "big picture, long-range campaign vision" that will guide the campaign to victory in November.

But sources close to the campaign told CNN that while Manafort and his deputy Rick Gates will remain on staff, they will return to their Washington, D.C. base largely sidelined.

Instead of Manafort's attempts to make Trump a more traditional candidate, Bannon will take over as Trump's top adviser, giving Trump free rein to run as the outsider candidate who won the Republican primaries.

Bannon's ascension solidifies an informal, mutually beneficial relationship between Breitbart, which has unapologetically championed Trump, and the campaign. The website, which Bannon has been closely involved with since its launch in 2007, has also been a center for conspiracy theories about Clinton's health as well as stories about Bill Clinton's alleged treatment of women.

The campaign's changes came as tensions mounted inside Trump's campaign in recent weeks and as Trump's relationship with Manafort soured to the point that several people close to the campaign warned that a major staff shake-up might be imminent, sources close to the campaign told CNN.

The staffing shake-up follows several weeks of negative headlines and alarming polls for Trump who is trailing Hillary Clinton, the Democratic nominee, in nearly every key battleground state and lagging in the latest national polls.

Trump decided on the changes this weekend after speaking with campaign donors at a fundraiser in The Hamptons, including Rebekah Mercer, a high-profile GOP donor with longstanding ties to Conway, who shared her concerns with Trump about the direction of the campaign, a source told CNN.

Trump then called Conway on Sunday from his golf club in Bedminster, New Jersey, to express his displeasure with the direction of his struggling campaign, sources close to the campaign said.

Notably, he made the decision without input from his adult children who were off traveling during the weekend, sources close to the campaign said.

Donald, Jr., Eric and Ivanka Trump have been influential advisers in the campaign and key mediators between Trump and Manafort, often also guiding their father to mollify his rhetoric and run a more conventional campaign.

Trump's call to Conway came the same day Trump also met with Ailes at the same golf club.

Returning from an overseas vacation, Trump' son-in-law Jared Kushner, a top campaign official, convened a meeting at Trump Tower with Manafort, Gates, Bannon and Conway on Trump's orders to announce the shift in roles, sources said.

The Trump campaign denied that Ailes would be taking on any role with the campaign and campaign aides also received a memo Tuesday slapping down those reports, according to a source close to the campaign.

In a statement from the campaign Wednesday morning outlining the changes, Trump said he was willing to do "whatever it takes to win this election."

"I have known Steve and Kellyanne both for many years. They are extremely capable, highly qualified people who love to win and know how to win," Trump said in the statement. "I believe we're adding some of the best talents in politics, with the experience and expertise needed to defeat Hillary Clinton in November and continue to share my message and vision to Make America Great Again."

Second major shake-up of the summer

The shake-up marks the second major change in the top rungs of the billionaire's campaign.

Trump just two months ago fired his campaign manager Corey Lewandowski after weeks of internal fighting between Lewandowski and Manafort, who was initially brought on to oversee Trump's efforts to stave off the possibility of a contested convention.

Corey Lewandowski was fired two months ago.

As the campaign shake-up neared, campaign aides pointed fingers at each other, the campaign's pollsters quarreled over strategy and the friction between Trump and Manafort became apparent.

Both Trump and Manafort discussed the friction in their relationship with friends in recent days, and a close associate described Trump as frustrated at the state of the race, leveling complaints that he has been the victim of bad advice from his political team.

"Mr. Trump doesn't trust him anymore. That's it. Pure and simple," a source familiar with the tensions told CNN, adding that Trump's gaffes and controversial statements in recent weeks have been fueled in part by his "exasperation" with the campaign's management.

"When Mr. Trump doesn't feel comfortable with the way things are managed or the way things are, he has a tendency to try to do everything, thus his exasperation becomes apparent. It manifests itself," the source said.

Paul Manafort stays on as the campaign's chairman.

Several people in touch with Trump or his top political advisers in recent days said they had heard a shake-up was possible. But some cautioned that such chatter was predictable and inevitable when any campaign faces tough times.

Rough few weeks for Trump

Trump's decision to overhaul his campaign's leadership came as recent polls showed Clinton thrashing Trump in the key battleground states and even gaining a lead in several states that typically lean Republican, such as Georgia.

And the decision also follows a slew of self-inflicted wounds since the Democratic National Convention wrapped, with Trump exchanging barbs with the parents of a slain US soldier, reigniting intra-party tensions by initially declining to endorse House Speaker Paul Ryan in his reelection bid and ultimately suggesting that "Second Amendment people" could act to keep Clinton from appointing liberal Supreme Court justices should she become president.

Trump's campaign advisers have sought to refocus him, including through a pair of scripted policy speeches on the economy and terrorism that offered a stark contrast to Trump's freewheeling style.

But Trump has repeatedly said he is resistant to change and reiterated that Tuesday in an interview with a local news station in Wisconsin.

"I am who I am. It's me. I don't want to change. Everyone talks about, 'Oh are you going to pivot?' I don't want to pivot. You have to be you. If you start pivoting you are not being honest with people," Trump told WKDT.

Lewandowski, who is now a CNN political commentator, has continued to informally advise Trump, according to sources familiar with their ongoing conversations.

Lewandowski said Tuesday evening on CNN that while Trump may try to be "more inclusive," Trump "knows who he is internally."

"What he's going to do is remain true to himself, which is what this campaign has been about," Lewandowski said.

Internal finger pointing abounded in recent days as recent media accounts have portrayed a campaign in disarray and at-times feuding with frustrated GOP leaders. Differences between the Trump campaign's pollsters Tony Fabrizio and Conway, who was promoted to campaign manager, were also the source of recent tensions.

The source noted that Lewandowski had issued a similar campaign memo when Manafort was hired in a volunteer capacity with the campaign.