WASHINGTON — John F. Kelly, President Trump’s new chief of staff, firmly asserted his authority on his first day in the White House on Monday, telling aides he will impose military discipline on a free-for-all West Wing and underscoring his intent by firing Anthony Scaramucci, the bombastic communications director, 10 days after he was hired.

Scaramucci was forced out of his post, with the blessing of the president and his family, just days after unloading a crude verbal tirade against other members of the president’s staff, including Reince Priebus, Kelly’s beleaguered predecessor, and Stephen Bannon, the chief White House strategist.

Trump recruited Scaramucci as a tough-talking alter ego who would ferociously fight for him the way others had not. But “the Mooch,’’ as he likes to be known, quickly went too far, even though working for a president who delights in pushing boundaries of political and social decorum. As Kelly, a former four-star Marine general, began his first day on the job, Sarah Huckabee Sanders, the White House press secretary, announced that Scaramucci was out.

“The president certainly felt that Anthony’s comments were inappropriate for a person in that position,’’ Sanders said. “He didn’t want to burden General Kelly, also, with that line of succession.’’

In a post to Twitter just hours before the announcement, Trump insisted that there had been “No WH chaos!’’ Yet even as he sought to reassure supporters that all was well, several administration aides fretted that the impetuous president and the disciplined Marine were already on a collision course that could doom the unlikely partnership.

Kelly, the first former general to occupy the gatekeeper’s post since Alexander Haig played that role for President Richard M. Nixon during Watergate, is charged with quelling the chaos that has defined, distracted, and often derailed Trump’s White House. But the president gave Priebus many of the same assurances of control, and then proceeded to undercut and ignore him — to the point where Priebus often positioned himself at the door of the Oval Office to find out whom the president was talking to.

Scaramucci epitomized the chaos of the West Wing. As a wealthy New York financier, he burst onto the political scene with a memorable performance in the White House briefing room, where he portrayed himself as a major, new player who had been assured he would report directly to the president, without the interference of intermediaries like Priebus or Sean Spicer, the president’s first press secretary.

Spicer had resigned just hours after Scaramucci’s hiring was made public. And shortly after Scaramucci called Priebus a “paranoid schizophrenic, a paranoiac’’ — adding a more vulgar term to the beginning of the phrase — Priebus, too, offered his resignation.

It was soon clear that Scaramucci would not be a fixture of the administration, but a transitory figure who created an opportunity for Trump, with his daughter Ivanka and son-in-law Jared Kushner, to undertake the far-reaching shake-up intended to purge the White House staff of leakers and aides viewed as not sufficiently loyal to his cause.

Kelly, who was Donald Trump’s first secretary of homeland security, arrives at a critical juncture, when the president is confronted with North Korea’s growing nuclear ambitions, Russia’s aggressive diplomatic moves, and continuing fighting in Iraq and Syria. The new chief of staff will also be charged with reviving a stalled legislative agenda. Trump’s campaign promise to repeal and replace the Affordable Care Act ended in failure last week, and there has been little progress on other major goals like tax reform or rebuilding the nation’s infrastructure.

And despite his desire for discipline, it took only hours Monday for Kelly to face his first White House leak, and it was about him. CNN reported that Kelly had been so upset about the president’s firing of James Comey, the former FBI director, in May that he called Comey to say he was considering resigning, an account that was confirmed by a former law enforcement official who was told of the conversation.

Kelly resisted the president’s entreaties to take over for Priebus during the past several weeks. After his appointment was announced Friday, he met with Trump and demanded assurances that he would wield the usual, sweeping authority over personnel, the flow of information, and access to the Oval Office that chiefs of staff have traditionally been given.

In early morning staff meetings at the White House on Monday, Kelly made it clear that the president had agreed to let him impose more discipline. Kelly also made it clear that everyone in the staff — including Bannon, Ivanka Trump, and Kushner — will clear policy proposals, personnel recommendations, and advice from outsiders through him.

While Kelly’s concerns were the decisive factor in Scaramucci’s departure, it was clear that Trump had quickly soured on the wisecracking, Long Island-bred former hedge fund manager, and so had his family, according to people involved in the White House’s internal discussions.

Donald Trump was initially pleased by Scaramucci’s harsh remarks, directed at Priebus as well as Bannon. But that view seemed to change as people around Trump told him that Scaramucci’s over-the-top performances were not well received. Over the weekend, after speaking with his family and Kelly — who refused to even consider retaining Scaramucci — the president began to see the brash actions of his newly high-profile subordinate as a political liability, according to three people familiar with his thinking.

After he was removed from his post Monday, Scaramucci was escorted from the White House grounds.

Also Monday, the lawyer for Scaramucci’s wife, Deidre Ball, who filed for divorce before the birth of the couple’s second child last week, denied reports that Scaramucci going to work for Trump was a factor in the divorce. Jill Stone would not characterize the nature of the separation. She said that Ball, who is in her late 30s, gave birth last Monday. The newborn was with her and was “doing very well,’’ Stone said.

The week of his son’s birth in New York coincided with his first week in the White House, and Scaramucci remained in Washington with the president. On the day his son was born, Scaramucci, 53, traveled aboard Air Force One with Trump, and then watched as the president delivered a politically charged speech to thousands of Boy Scouts in West Virginia.

►Trump dictated statement on son’s meeting with Russian. A6

Material from the Associated Press was used in this report.