President Donald Trump reportedly tapped Mick Mulvaney, the director of the Office of Management and Budget, to become his next White House chief of staff after growing frustrated that none of his top candidates would accept the position.

Unlike other high-profile candidates who were considered for the position, Mulvaney was not formally interviewed, officials said.

Despite Trump's assurances that the vacancy was highly desired, some Democratic lawmakers not persuaded.

President Donald Trump abruptly tapped Mick Mulvaney, the director of the Office of Management and Budget, to become his next White House chief of staff after growing frustrated that none of his top candidates would accept the position, a senior White House official said in a Washington Post report on Friday.

Following multiple rejections this week from candidates who were on his short list — including former Gov. Chris Christie of New Jersey and Vice President Mike Pence's chief of staff Nick Ayers — Trump became agitated by the news reports that painted an unflattering picture of what was supposed to be a highly sought-after job, the senior White House official reportedly said.

On Friday afternoon, Trump announced on Twitter that Mulvaney would take over as acting White House chief of staff, which was formally held by former four-star Marine Corps general John Kelly. The decision capped off a week's worth of speculation over who would replace Kelly, who was expected to leave the West Wing by December after a litany of reports of a rift with Trump and his staff.

Unlike other high-profile candidates who were considered for the position, Mulvaney was not formally interviewed, officials said to The Post. He talked with Trump on Friday for a scheduled meeting about the federal budget and then became acting chief of staff.

But one person familiar with the discussions claimed that Mulvaney actively lobbied for the position, according to New York Times correspondent Maggie Haberman, and pointed to a lack of scandals stemming from the budget office as a qualification for the job.

"I look forward to working with him in this new capacity as we continue to MAKE AMERICA GREAT AGAIN!" Trump said on Twitter.

Incoming acting White House chief of staff Mick Mulvaney. Astrid Riecken/Getty Images

Two hours after his announcement, Trump appeared to address skeptics who questioned the timing of Mulvaney's appointment and qualifications: "For the record, there were MANY people who wanted to be the White House Chief of Staff. Mick M will do a GREAT job!"

Despite Trump's assurances, some Democratic lawmakers are not persuaded.

"Very sad not a single person in America will agree to be [White House] chief of staff, formerly one of the most sought-after jobs in government," Sen. Chuck Schumer of New York said on Twitter.

"Very troubling (but not surprising!) [Donald Trump] chose Mick Mulvaney to be acting [chief of staff]. He's been a leading advocate of government shutdowns," Schumer added.

"Unlike cabinet officials, Mick Mulvaney does not need to be confirmed," Rep. Ted Lieu of California tweeted. "That means he doesn't need to be 'Acting' Chief of Staff, he can simply be Chief of Staff. Unless you are hedging because you're not too sure about him."

A senior White House official told reporters Mulvaney would assume the responsibilities of a formal chief of staff and that his interim role would have "no time limit."

"He's the acting chief of staff, which means he's the chief of staff," the official said. "He got picked because the president liked him they get along."

White House press secretary Sarah Huckabee Sanders added that Mulvaney will not resign as overseer of the federal budget in the Office of Management and Budget, "but will spend all of his time devoted" to his new role. Russell Vought, the Management and Budget's deputy director, is expected to assume the day-to-day operations of the agency.

Mulvaney, a former Republican representative of South Carolina, took on numerous roles in the Trump administration and is widely seen as a fiscal conservative willing to curb federal spending. As the acting director of the Consumer Financial Protection Bureau, he gutted the watchdog's 25-member advisory board after members criticized the agency's leadership, and is believed to be slow-walking regulatory practices and investigations.