U.S. President Donald Trump announced Mick Mulvaney, director of the Office of Management and Budget (OMB), as new acting White House chief of staff via Twitter on Friday.
Trump said Mulvaney has done an “outstanding job” in the administration.
Mulvaney responded to the news on Twitter, saying it is a “tremendous honor” and he looks forward to working with Trump and his team.
Mulvaney will replace John Kelly, who Trump announced last week would be leaving his role by the end of the year. Trump thanked Kelly for his service on Twitter and said he is a “GREAT PATRIOT.”
WATCH: Trump says he’s narrowed chief of staff shortlist to 5, says Michael Flynn is a ‘great person’
Kelly, a retired general and former secretary of the Department of Homeland Security, had been chief of staff since July 2017. He replaced Reince Priebus, who had the job for six months.
Mulvaney will be Trump’s third chief of staff.
A White House official told reporters there is “no time limit” on his appointment.
“He’s the acting chief of staff, which means he’s the chief of staff. He got picked because the president liked him. They get along,” the official said.
Before joining the administration, Mulvaney was an outspoken member of the House Freedom Caucus, a powerful bloc of Republican lawmakers in the House of Representatives. He helped orchestrate a government shutdown in 2013 with the Freedom Caucus as a protest against funding for then-U.S. President Barack Obama’s healthcare law.
He often appears on Sunday television talk shows to defend Trump’s policies.
WATCH: Several candidates are being considered after Trump’s top pick for chief of staff turns down the job
Mulvaney will remain as OMB director, and his deputy, Russ Vought, will handle the office’s day-to-day operations, White House spokeswoman Sarah Sanders said.
Trump had already gone through a couple of candidates before announcing Mulvaney’s new role. He had previously considered U.S. Vice-President Mike Pence’s aide, Nick Ayers, for the position but had to turn to other candidates after they could not agree on his length of service.
Former New Jersey governor Chris Christie had also been considered, but he withdrew himself from consideration hours before Mulvaney was announced as a replacement Friday. Trump’s son-in-law Jared Kushner had reportedly been a possible contender as well.
WATCH: Chief of staff John Kelly will be leaving at the end of the year, Trump says
Trump denied that there was trouble filling the chief of staff role, saying “For the record, there were MANY people who wanted to be the White House Chief of Staff,” on Twitter.
This is not the first time Trump has turned to Mulvaney in a pinch. Last November, he named Mulvaney the acting head of the Consumer Financial Protection Bureau.
It was an appointment that was fought in court, but Mulvaney prevailed and ran it until earlier this month, when Trump’s official pick was confirmed by the U.S. Senate.
Trump is not alone though in promoting an OMB director to chief of staff. Former President Bill Clinton elevated his OMB director, Leon Panetta, to the job, as did Obama with Jack Lew.
The White House chief of staff position is considered one of the most important in Washington because its occupant carries out the president’s priorities and ensures he has the right information to make decisions.
Under Trump, the chief of staff has been heavily involved in damage control and attempting to manage what has been a chaotic presidency.
Kelly had been credited with using an iron fist while in the job to impose order, but over time had grown increasingly isolated.
-With files from Reuters