The president had believed that after he announced last week the former Marine Corps general would leave the White House by the end of the year – there had been speculation about the 68-year-old for months – the job would be filled by Nick Ayers. But Mr Ayers, 36, a tough Republican strategist who currently serves as the vice president’s chief of staff, announced he would not be taking the job after failing to agree terms with the president.
At that point, attention turned to treasury secretary Steven Mnuchin, conservative congressman Mark Meadows and US trade representative Robert Lighthizer. Reports suggested former New Jersey governor Chris Christie, who was once close to Mr Trump but later sidelined after the 2016 election, was also being considered.
On Friday morning, Mr Christie has pulled himself out of consideration, saying it had been “an honour” to have been considered for the position. He said he had told Mr Trump that “now is not the right time for me or my family to undertake this serious assignment” and he asked the president to “no longer keep me in any of his considerations for this post”.
On Friday evening, Mr Trump announced he had chosen Mr Mulvaney, another person whose name had been mentioned by some as among the candidates being considered by the president.
“I am pleased to announce that Mick Mulvaney, director of the office of management and budget, will be named acting White House chief of staff, replacing General John Kelly, who has served our country with distinction,” Mr Trump wrote on Twitter.
He added: “I look forward to working with him in this new capacity as we continue to MAKE AMERICA GREAT AGAIN! John will be staying until the end of the year. He is a GREAT PATRIOT and I want to personally thank him for his service!”
Mr Mulvaney, a former three-term congressman from South Carolina, became the director of Mr Trump’s office of management and budget shortly after the president took office.
He will become Mr Trump’s third chief of staff, after Mr Kelly and Reince Priebus. Mr Kelly, who took on the job in July last year, was brought in to bring about order after several months of sheer turbulence in the White House, when Mr Priebus, tried in vain to juggle the West Wing’s various factions.
Mr Priebus later told Chris Whipple, author of a book on White House chiefs of staff entitled The Gatekeepers: “Take everything you’ve heard and multiply it by 50.”
The job is considered grinding at the best of times; Barack Obama had five such people serve in the position during his two terms.
But the job Mr Mulvaney is taking on will be even more challenging. Mr Trump infamously hates to be managed and likes to make policy decisions on the whim, sometimes leaving his staff struggling to catch up.
Meanwhile, he will be arriving as the White House is beset with a number of major challenges – a newly resurgent Democratic party about to take control of the House of Representatives, special counsel Robert Muller’s investigation, and an economy many believe be about to hit the rails.
David Corn, political editor of Mother Jones magazine, told The Independent of the search for a chief of staff: “I can’t figure out for the life of me any accomplished and serious person who would want to take on that job. Few leave the Trump administration with their reputations – and perhaps even their souls – unscathed. It’s true mystery. But ambition can always find a date.”