President-elect Donald Trump, retired U.S. Army Lt. Gen. Michael T. Flynn and Chief of Staff Reince Priebus walk out to speak to members of the media at the Mar-a-Lago club on Wednesday, Dec. 21, 2016. (Jabin Botsford/The Washington Post)

Reince Priebus says that one of his most important tasks as Donald Trump’s chief of staff will be to establish “some level of order within the White House.”

That, of course, has been the central mission of everyone who has held this post in the past, but it is certain to be a particularly daunting challenge with a president who regards chaos as a management tool.

Trump’s Twitter feed is a daily, sometimes hourly, testament to his impulsive nature, his disregard for norms and protocol, his bottomless appetite for random information and misinformation.

Adding to the potential for tension is the fact that Trump’s White House is being set up with rival centers of gravity.

The structure puts Priebus on the same level as Stephen K. Bannon, whom Trump named to be his senior counselor and chief strategist. Bannon is the former chairman of Breitbart News, a media voice of the alt-right, which is a fiery fringe movement that embraces elements of white nationalism. Though the post-election announcement of Trump’s White House team described Bannon and Priebus as “equal partners to transform the federal government,” it listed Bannon first.

(Bastien Inzaurralde/The Washington Post)

Trump’s son-in-law and consigliere Jared Kushner is also expected to be close by in some kind of capacity that will give him a say in major decisions.

None of the three has ever worked in a White House.

All of this means that the 44-year-old Priebus will be at the center of an experiment to determine whether Trump’s singular style of leadership — honed in his family business, displayed on reality television, and used with devastating effect in a presidential campaign that defied every expectation — will transform Washington as Trump promised or prove ineffective when applied to the more complex work of presiding over the massive federal government.

The role in Trump’s inner sanctum is, by some measures, a surprising spot for Priebus. After the party’s 2012 defeat, the party chairman presided over an autopsy report that called for courting minorities by, among other things, embracing looser immigration laws. Trump, who campaigned on building a wall on the U.S.-Mexico border and endorsed mass deportations, effectively rejected the recommendation — and won anyway.

The power-sharing dynamic between Priebus and his new colleagues looks worrisome to those who have had Priebus’s title in prior administrations. Some predict flatly that it will not work.

“The president has to make it clear that Reince is first among equals,” said Ken Duberstein, who served as chief of staff under Ronald Reagan. “You’ve got to empower somebody on the staff.”

“The chief of staff, I think, has the responsibility to be all-knowing — to decide what the president should know, what he needs to know, what he doesn’t need to know,” agreed Andrew Card, who ran George W. Bush’s White House staff for 5 1 /2 years, the second-longest tenure of any chief of staff in modern history.

1 of 35 Full Screen Autoplay Close Skip Ad × Here’s a look at Trump’s administration so far View Photos The men and women the president-elect has selected for his Cabinet and White House team. Caption The men and women the president-elect has selected for his Cabinet and White House team. Scott Gottlieb, nominee for commissioner of FDA President Trump is set to nominate Scott Gottlieb, a conservative physician and businessman with deep ties to the pharmaceutical industry, to be commissioner of the Food and Drug Administration, a White House official said. Courtesy of American Enterprise Institute/via Reuters Buy Photo Wait 1 second to continue.

Ambiguous lines of authority, Card added, are likely to be “a challenge.”

“In my opinion, there can only be one chief of staff,” Card said.

Priebus, however, brushes off the skepticism.

“Bannon, Jared and I work together extremely well,” he said in an interview. “We’ve got a good team of people around [Trump] where we respect each other and we present options for him that I think he looks at and says, ‘Well, if these folks are on the same page, then it’s probably a pretty good option to take.’ ”

But Trump is also known for being swayed by the last person he has talked to, especially if the advice is accompanied by flattery. In his White House, an array of people, some with strong personalities, are expected to have coveted walk-in privileges to bring their viewpoints directly to the Oval Office. Besides Bannon and Kushner, this will probably include counselor Kellyanne Conway, policy adviser Stephen Miller, national security adviser Michael T. Flynn and counterterrorism adviser Thomas Bossert.

Trump’s spokesmen did not respond to a request to interview the president-elect about his relationship with Priebus, or how Trump envisions Priebus’s role.

Historically, a White House chief of staff is often the first to be blamed when something goes wrong. It is a burnout job. Even successful ones rarely last more than a couple of years.

Priebus, with a buttoned-up Midwestern bearing, has demonstrated a mastery of internal politics. His tenacity has been tested by the fact that he has survived six turbulent years — a record — as chairman of the Republican National Committee.

“Reince has this kind of ‘aw, shucks’ demeanor, but he’s pretty tough,” said former RNC chairman Ed Gillespie.

Wisconsin assembly Speaker Robin Vos, who was a college roommate of Priebus’s, described him as “a shrewd operator, in the best sense of the word.”

This side of Priebus was not always apparent over the past year. He often seemed like a hapless passenger, along for the wild ride that was Trump’s candidacy. Priebus joked that it wasn’t all that bad — he had not yet taken to pouring Baileys Irish Cream on his cereal in the morning.

The GOP chairman’s plight became so comedic that host Stephen Colbert and actor Tom Hanks tried that recipe of whiskey-and-cream liqueur over Lucky Charms on the “Late Show.” Colbert said: “They’re going to be serving this at the convention, as part of the suicide pact.” Hanks pronounced it “friggin’ delicious” and said he would start voting Republican.

Priebus does not deny published accounts of one particularly low moment, which came in the wake of The Washington Post’s Oct. 8 revelation of a 2005 tape in which Trump was heard making lewd comments about women and boasting of groping them. The distraught party chairman reportedly urged the GOP nominee to drop out of the race, or face losing it in a landslide.

“I’m not going to talk about private conversations,” Priebus said when asked if it was true. “Sure, I mean I was nervous about it, like everybody was, and he apologized for it, and we started doing debate prep again the next day. And he just killed it in the second debate. He did such a great job, and he addressed it, and he did so, I think, like a champion, and he moved forward.”

Building a relationship

Going back to Priebus’s early days as party chairman in 2011, Trump Tower had been a regular stop on his fundraising rounds. When Priebus made the pilgrimage to Manhattan in early 2015, he noticed something seemed different about Trump.

The celebrity real estate developer had flirted with a presidential run so many times before that no one gave the idea much credence anymore. But Trump’s questions about the primary process struck Priebus as unusually detailed and pointed: How did the Iowa caucuses work? How were delegates awarded? Did straw polls matter?

“I left, and I started wondering whether he was actually getting very serious about running,” Priebus recalled.

It would soon become apparent that he was, and as the campaign unfolded, Priebus began talking to Trump far more frequently than the other contenders.

“Perhaps some of the reason we became close is that he wasn’t as rigid as a lot of the people running for president,” Priebus said. “They were very controlled. They’re trained to be at arm’s length, even if you’re friends with them. Set up a phone call at 4:30 tomorrow to talk for 15 minutes to somebody. That’s just not the way that President-elect Trump runs.”

Early on, Priebus used some of those sessions to urge Trump to tamp down his incendiary and divisive rhetoric. That turned out to be futile.

“Yes, occasionally we had disagreements along the way,” Priebus said. “We ended up creating a relationship where our front-runner felt comfortable with the chairman of the party, and the chairman of the party felt comfortable with a front-runner that was not the typical plasticized Washington politician.”

‘The ultimate diplomat’

The Trump-Priebus relationship has had its rough patches during the campaign, but in one important regard, it also turned out to be what Priebus called “a perfect marriage.”

As he had dug the Republican Party out of debt, Priebus had been working for years to construct the kind of political infrastructure Trump’s campaign had neither the resources nor the inclination to build for itself. Such unglamorous basics as ground operation and data collection were a badly needed asset in some of the close states Trump needed to put him over 270 electoral votes.

“The party had to be just about perfect to win. The Democrats can be good and still win, but we have to be about perfect in order to win,” Priebus said. “It just turns out that the president-elect’s message was ringing extremely true to the electorate and we had the data and the infrastructure to back it up.”

And from the time when it had become clear that the New York real estate mogul would be the 2016 standard-bearer for a party whose establishment he had trashed, Priebus had taken on the difficult task of tugging the warring GOP factions toward reconciliation and acceptance, if not enthusiasm.

One of this most important projects was bringing aboard key party leaders in Priebus’s home state of Wisconsin, which had gone for Sen. Ted Cruz (R-Tex.) in the primary and where Trump had been at war with major political figures. The most important target, allies said, was House Speaker Paul D. Ryan (R-Wis.).

Priebus “was the ultimate diplomat,” said Wisconsin Gov. Scott Walker, whose own 2016 presidential hopes had fallen early victim to Trump. “Paul’s support was critical to sending a message, not just to House members, but just overall Republican voters. Reince was just tenacious.”

Vos, like many prominent Wisconsin Republicans, had supported Walker, then Sen. Marco Rubio (R-Fla.), then Cruz, only to see each of their hopes incinerated in the anti-establishment brushfire that Trump had ignited.

“As soon as Donald Trump became the presumptive nominee, he was all over me,” Vos said of Priebus. “I said, ‘I’ll take whatever you got.’ ”

Trump carried Wisconsin by less than a percentage point, becoming the first Republican to do so since Ronald Reagan in 1984.

As Trump and his team have turned to governing, people knowledgeable about the internal deliberations of the transition say, Priebus has more often than not gotten his way on key administration hires. Several of his top aides are being lined up for big jobs in the White House. Most notable thus far has been RNC communications director and Priebus confidant Sean Spicer as press secretary. Katie Walsh, currently Priebus’s chief of staff at the RNC, is considered likely to become a deputy White House chief of staff.

Trump’s naming of Priebus sent a reassuring signal to the Washington establishment, including Ryan, whose ability to work with Trump is going to be vital to Republicans getting anything done.

Priebus said his new job was not the result of outside lobbying, but “all a matter of Donald Trump’s opinion.”

Politics in his blood

Priebus grew up in historically Democratic blue-collar Kenosha, the son of a German American electrician father and a Greek mother born in Africa. His first name is short for Reinhold.

He was campaign chairman for Ronald Reagan in his third-grade mock election, listened to speeches by rising GOP firebrand Newt Gingrich on cassettes in his car as a teenager, and took his future wife, Sally, to a party fundraiser on their first date.

Priebus had nurtured a dream of being elected to office himself some day but lost a close race for state Senate in 2004, forcing him to recalibrate his ambitions and rechannel his love of politics.

In 2007, he became Wisconsin party chairman at the beginning of a turbulent era in that state’s politics, requiring some of the rough-water navigation skills he would later need on the national level.

Though Priebus had establishment credentials as a lawyer with one of the state’s big firms, he also became a regular presence at tea party rallies and grass-roots gatherings.

“He was this interesting mix,” said Walker, who was a legislator and county executive during those early years. “You’d think, historically, people like that are raising money. They’re good at knowing the major power players in the Milwaukee area. Reince could do all that. He was also very much connected to the grass roots and the true believers.”

Priebus, as a result, shared in the credit for the 2010 election of tea party favorites Walker and Sen. Ron Johnson. And for helping Walker weather a recall effort.

Those successes made him something of a star in GOP circles. He became RNC chairman in 2011 at a desperate time for the party, which was $24 million in debt. It had a little more than $350,000 cash on hand and a $400,000 payroll due six days later — a situation so dire that, early on, he had to help float it by maxing out two personal credit cards to pay his travel expenses.

“When you don’t have the White House and you don’t have the Congress, dialing for money is just hard as hell, and he just kept doing it, and he didn’t have anybody helping him,” said lobbyist Richard Hohlt. “He loved the job.”

By the end of 2012, the RNC has $3.3 million in the bank and no debt.

As different as he is from Trump, Priebus shares one thing with the president-elect: little apparent need for sleep. Walker marveled at how he has texted Priebus at 11 p.m. on a Saturday, gotten an immediate response, and then awakened to a follow-up sent at dawn.

That means that when the future president is firing off tweets in the wee hours, as is his wont, his chief of staff will probably be up and seeing them.

The two also will be learning the fundamentals of their jobs together. At a recent lunch with former White House chiefs of staff, hosted by the current one, Denis McDonough, Priebus peppered his predecessors with basic questions, according to three sources with knowledge of what was said during the private session. Among his queries: How do you involve Cabinet officials, and make sure they are pursuing the president’s agenda, rather than their own? Who are the most crucial allies to have in the building? How do you control who gets the president’s ear?

What is paramount, said former chief of staff Card, is that no one be allowed to make end runs around Priebus.

“Almost no debate in the Oval Office should come without a prior debate in the chief of staff’s office,” Card said. “It is going to be a challenge for Reince.”

Priebus disagreed.

“No, I don’t think it’s a particular challenge,” he said, promising “an orderly system in place in which the president is informed, and not exhausted with multiple sources of information in an unorganized fashion.”

There was that word again: order. Achieving it could determine Trump’s success. And the responsibility for making it happen will be riding on his chief of staff, who might want to keep a bottle of Baileys handy, just in case.

Robert Costa contributed to this report.