In a surprise move, President Donald Trump on Friday named U.S. Rep. Mark Meadows his new chief of staff, replacing acting chief Mick Mulvaney.

Trump also announced on Twitter that Mulvaney would become U.S. special envoy for Northern Ireland.

Trump did not give a reason for why he replaced Mulvaney, who technically remains the director of Office of Management and Budget.

....I want to thank Acting Chief Mick Mulvaney for having served the Administration so well. He will become the United States Special Envoy for Northern Ireland. Thank you!
— Donald J. Trump (@realDonaldTrump) March 7, 2020

A request for comment from Meadows, who represents North Carolina, was not immediately returned Friday night.

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Meadows is considered one of Trump’s staunchest congressional allies. Meadows announced in December that he would not seek re-election in 2020. At the time, Meadows suggested that he could have a role in helping the president.

The lawmaker said then that his “work with President Trump and his administration is only beginning."

"This President has accomplished incredible results for the country in just 3 years, and I'm fully committed to staying in the fight with him and his team to build on those successes and deliver on his promises for the years to come," Meadows said in the December statement.
Acting White House Chief of Staff Mick Mulvaney listens during a cabinet meeting held by President Donald Trump at the White House on Oct. 21, 2019.Leah Millis / Reuters file

Mulvaney became Trump's chief of staff in December 2018, after the president announced that John Kelly, his second chief of staff, was to leave at the end of that year.

Trump’s first chief of staff, Reince Priebus, was removed by the president in July 2017 after six months on the job.

Trump was asked in early February whether Mulvaney would stay on as chief of staff, and the president responded “That was a false report. I have a great relationship with Mick,” according to a White House transcript.

In December, Mulvaney seemed to admit that the withholding of military aid to Ukraine was tied to demands that the country investigate a conspiracy theory about the 2016 election.

"We do that all the time with foreign policy," Mulvaney said at that news conference.

"Get over it," he said. "There’s going to be political influence in foreign policy."

Mulvaney later tried to walk back the remarks. "There was absolutely no quid pro quo between Ukrainian military aid and any investigation into the 2016 election," he said.

But Mulvaney's admission angered and confused Trump allies inside and outside the administration, according to two people familiar with the matter. One of them called Mulvaney’s comments in the White House briefing room "an unmitigated disaster."

The withholding of military aid to Ukraine and alleged pressure to investigate the 2016 theory and announce investigations into Joe Biden and his son were central to the impeachment of Trump by the House. Critics accused Trump abusing the power of his presidency for personal political gain.

The articles of impeachment charged Trump with abuse of power and obstruction of Congress. The Republican-held Senate acquitted the president in February.

Trump Friday night thanked Mulvaney “for having served the Administration so well."

Meadows was a founding member of the House Freedom Caucus. Fellow leading caucus member Rep. Jim Jordan, R-Ohio, who is also a vocal defender of the president, tweeted Friday night that Trump “couldn’t have picked anyone better for the job.”