Still, the public airing of grievances was perhaps an inevitable clash between two temperamentally similar but philosophically different alpha males who for almost six months have been nearly inseparable despite lacking any previous relationship to speak of.
Some view the relationship as dysfunctional. When a president’s chief of staff speaks to members of Congress, it should be a “consistent message,” Representative Henry Cuellar, Democrat of Texas, said in an interview with CNN. The inconsistency, said Mr. Cuellar, who attended the meeting on Wednesday where Mr. Kelly made some of his remarks, “makes it hard” to negotiate.
Both Mr. Trump and Mr. Kelly are used to being in charge, and both are prone to dramatic outbursts of temper, according to interviews with a half-dozen White House officials. Both have a tendency to say different things to different audiences, and Mr. Kelly is more strident about the need to restrict immigration than some people had realized.
They depart over governing philosophy: Mr. Trump favors chaos, and Mr. Kelly believes in strict command and control. And while Mr. Trump believes in his abilities as a salesman, Mr. Kelly is unused to being thrust in front of the national cameras.
Many members of Congress, like Mr. Cuellar, had expected Mr. Kelly to be a force for stability in a White House that has at times seemed consumed with dysfunction, but have found a different reality.
“He brought some order to the chaos that was there, but it’s a long way from a functioning White House,” said Senator Richard J. Durbin of Illinois, the second-ranking Democrat, said in an interview for “The Daily,” a New York Times podcast. “His role from time to time I’ve considered to be destructive, sometimes constructive. I wonder, you know, if he really is the man I thought he was when I voted for him as secretary of D.H.S.”
Mr. Durbin, who has clashed with Mr. Trump over his assertion that the president used a vulgar term in an immigration meeting last week, was referring to the Department of Homeland Security, which Mr. Kelly led before taking his current position.
Mr. Kelly, who declined to be interviewed for this article, has made little secret of the fact that he never wanted to be White House chief of staff, and took the job out of the same sense of duty that led him to a four-decade career in the Marines.
In the West Wing, Mr. Kelly seldom allows the staff to forget the dynamic, according to people who have observed him, often positioning himself as a one-man check against dangerous or reckless moves by the commander in chief. His loyalty is not to the president, “but to the Constitution and the country,” he has said, according to two people with direct knowledge of his remarks.
Mr. Kelly, officials say, has made a conscious decision not to focus as much on curbing the president’s penchant for tweeting or saying inflammatory things, and to instead pour his efforts into controlling who sees and talks to Mr. Trump and trying to shape his thinking on key issues.
“I have said many times I was not put in this job to change the way the president of the United States does business,” he said in an interview with Fox News on Wednesday. “I was put in the job to make sure the staff process better informs him on a range of issues.”
“Let Trump be Trump,” one White House official said on Thursday, summarizing Mr. Kelly’s approach to managing the president’s behavior. One senior administration official called it a “blind spot.”
Mr. Kelly has had successes at bringing tighter control and implementing systems in a chaotic White House, removing disruptive and seemingly immovable staff members such as Omarosa Manigault Newman, and overseeing the process of pushing a tax bill through Congress.
Early in his tenure, Mr. Kelly frequently threatened to quit as a way of getting people, particularly the president, to follow his orders, according to four people close to Mr. Trump. One adviser to the president said that it was among the few weapons in Mr. Kelly’s arsenal, and another said that he used it less regularly now. Mr. Kelly has denied in the past to The New York Times that he ever threatened to quit.
But he has been known to storm out of meetings or briefings if they take a direction he doesn’t like, other advisers said.
Some White House officials believe that Mr. Kelly has been hurt by the extraordinarily high expectations many had that he would bring discipline and moderation to a freewheeling White House that had previously empowered the most extreme voices. His inability to do that has left some staff members demoralized.
Others describe themselves as feeling safer, particularly compared to the period when Stephen K. Bannon, the former chief strategist, and Mr. Trump’s son-in-law, Jared Kushner, were constantly at war using damaging leaks. And nearly all say that Mr. Kelly has brought a semblance of order to a White House in which people during the first weeks of the Trump presidency wandered through without appointments, dropping things off for the president or showing up in the Oval Office unannounced.
But many at the White House say that Mr. Kelly has benefited too much from the constant comparison to Mr. Priebus and that morale has grown worse in the nearly six months that Mr. Kelly has had the job.
This is partly a result of exhaustion, and many staff members interviewed for this article said they were beginning a second year at the White House with less a sense of excitement and purpose than dread.
Some aides also say that for weeks Mr. Trump has been fielding complaints from allies and staff members about the strictures Mr. Kelly has placed on access to the president and his enforcement of a chain of command.
Mr. Kelly has been unable to fill a number of White House jobs, and talented and capable people who understand Mr. Trump are in short supply. People have warned the president that he faces a staff exodus among senior officials, who are worn down by a year in the White House and dismayed that the work environment has not gotten better, according to three people familiar with those conversations.
Yet some of Mr. Trump’s longest-serving aides are said to work well with Mr. Kelly. Kellyanne Conway, the White House counselor, has repeatedly praised him. And Donald F. McGahn II, the White House counsel, who had at one point considered leaving, has told the Senate majority leader, Mitch McConnell, and others that he likes Mr. Kelly and would stay if he remains.
Mr. Kelly told Fox News on Wednesday that he planned to do just that.
“I am in this for the long haul,” Mr. Kelly said. “It is the most important thing I’ve ever done in my life. Because if the administration fails, if the president of the United States is uninformed one time and makes the wrong decision, that’s on me.”