Many of them are people used to getting their way but will now have a boss to answer to — Trump — while navigating the sometimes frustrating and sprawling bureaucracy of the U.S. government. The incoming Trump administration is poised to undo as much of President Barack Obama's accomplishments as possible, while also attempting to advance a conservative policy agenda in areas such as taxes and healthcare.
A former senior U.S. official who knows Rex Tillerson, the former Exxon Mobil CEO who is Trump's nominee for secretary of State, and Marine General James Mattis, Trump's pick for Defense secretary, predicted a massive clash of egos in the cabinet.
Tillerson and Mattis are "accustomed to dominating whatever space they find themselves in, and that probably will now include the Situation Room and even the Oval Office."
Trump's transition team has said the cabinet is intended to be a mix of experienced Washington hands and newcomers. But former presidents who brought in outside blood have at times seen political neophytes make costly errors, experts said.
Of the 21 cabinet members and White House advisers chosen to date by Trump, 16 are white men. There are four women, none of whom hold what might be considered a top-tier agency post. There is one African-American, one Asian-American and one Indian-American. There are no Hispanics.
Like the real-estate magnate who chose them, several have no government experience. Others have been hostile toward the agencies they will lead if the U.S. Senate confirms them early next year.
Julian Zelizer, a presidential historian at Princeton University, said Trump is building a cabinet in his own image: blunt-talkers with real-world experience.
"Surrounding yourself with military guys and money guys sends a certain message," Zelizer said. "A certain kind of cutthroat aggressive dealmaker is how [Trump] imagines himself to be."
Obama, who leaves office in January, relied on experienced hands to form his cabinet in 2008. He named his rival for the Democratic presidential nomination, Hillary Clinton, as his secretary of state. Robert Gates, who served the previous administration, remained at the Pentagon, and Obama made longtime Justice Department official Eric Holder attorney general.
Some of Trump's picks do have similar experience, and he has packed his on-the-ground transition teams at various agencies with government veterans and ex-lobbyists, a Reuters review found earlier this month.
The newcomers to Washington will rise to the administrative challenge, said those who know them.
Republican Representative Tom Price, Trump's choice to lead the Department of Health and Human Services, is "decisive by nature," said fellow Republican lawmaker Tom Cole. He credited Price's career as a surgeon, which is also the former profession of Ben Carson, Trump's choice for secretary of Housing and Urban Development.
Carson, said Henry Brem, a neurosurgeon who worked with Carson at Johns Hopkins Hospital in Baltimore, has a "cool head" and is unafraid to give strong opinions. "He's a gentleman, he speaks his mind, he has great ideas — and nobody in the world intimidates him," he said.
Rick Perry, Trump's choice for Energy secretary, served three terms as governor of Texas and had to "balance a very conservative and increasingly ideological grassroots (support base) with a very influential business community," said James Henson, director of the Texas Politics Project at the University of Texas at Austin.
Whether he can do that do that in a bureaucratic setting, in an environment as competitive as a cabinet with a lot of obviously large egos, I think is another question," Henson said.
Several of Trump's picks have never held any sort of government post and have little, if any, background in policy-making, including Tillerson, Treasury nominee Steven Mnuchin, a Goldman Sachs alumnus, Commerce pick Wilbur Ross, a billionaire investor, and Gary Cohn, the Goldman Sachs executive who would chair Trump's economic council.
In 2008, Mnuchin purchased IndyMac, a lender that failed during the financial crisis and helped transform it into OneWest, now a thriving retail bank in southern California.
Kevin Kelly, a managing partner at Recon Capital Partners, an investment firm in Stamford, Connecticut, said that kind of real-world savvy could make government more effective.
Those with high-level corporate experience are used to having to please shareholders, board members, employees, and the community, Kelly said. "It takes a very precise and dedicated person to deliver across those constituencies."
Too much disruption?
The outsider approach hasn't always worked. In 2001, President George W. Bush's Treasury secretary, Paul O'Neill, the former chief executive of aluminum producer Alcoa, rattled markets with a series of careless remarks that seemed to herald economic policy shifts that differed with the White House's stance. He ultimately was fired.
"Management of large, public agencies is really difficult and requires bringing in experienced and knowledgeable people and working in ways that doesn't alienate people," said Thomas Mann, an expert on governance at the Brookings Institution.
Anthony Scaramucci, an adviser to the Trump transition, has acknowledged that too much inexperience could be harmful to Trump's young administration.
"Washington is a very healthy immunological system," he said. "You'll see a full-blown organ rejection if you put too many status-quo disruptors in Washington."