Top economic adviser Gary Cohn is leaving the White House after breaking with President Donald Trump on trade policy, the latest in a string of high-level departures from the West Wing.
The director of the National Economic Council has been the leading internal opponent to Mr Trump's planned tariffs on imports of steel and aluminium, working to orchestrate an eleventh-hour effort in recent days to get the president to reverse course.
But Mr Trump resisted those efforts, and reiterated on Tuesday he will be imposing tariffs in the coming days.
Mr Cohn's departure comes amid a period of unparalleled tumult in Mr Trump's administration and aides worry that more staffers may soon head for the doors.
The announcement came hours after Mr Trump denied there was chaos in the White House.
The president maintained that his White House has "tremendous energy," but multiple White House officials said Mr Trump has been urging anxious aides to stay.
"Everyone wants to work in the White House," Mr Trump said during a joint press conference with Swedish Prime Minister Stefan Lofven. "They all want a piece of the Oval Office."
In a statement, Mr Cohn said it was his honour to serve in the administration and "enact pro-growth economic policies to benefit the American people".
Mr Trump praised Mr Cohn despite the disagreement on trade, issuing a statement saying Mr Cohn has "served his country with great distinction".
Mr Cohn is a former Goldman Sachs executive who joined the White House after departing the Wall Street firm with a 285 million dollar (£205m) payout.
He played a pivotal role in helping Mr Trump enact a sweeping tax overhaul, coordinating with members of Congress.
Mr Cohn nearly departed the administration last summer after he was upset by the president's comments about the racial violence in Charlottesville, Virginia. Mr Cohn, who is Jewish, wrote a letter of resignation but never submitted it.
"Citizens standing up for equality and freedom can never be equated with white supremacists, neo-Nazis, and the KKK," Mr Cohn told The Financial Times at the time.
"I believe this administration can and must do better in consistently and unequivocally condemning these groups and do everything we can to heal the deep divisions that exist in our communities."
In a tweet earlier on Tuesday, Mr Trump sought to portray himself as the architect of the White House staff changes, writing: "I still have some people that I want to change (always seeking perfection)."
The president acknowledged he is a tough boss to work for, saying he enjoys watching his closest aides fight over policy. "I like conflict," he said during the press conference.
Mr Cohn was nowhere in sight at the press conference and a seat reserved for him in the East Room was filled by a different aide.
Dating back to the campaign, Mr Trump has frequently and loudly complained about the quality of his staff, eager to fault his aides for any mishaps rather than acknowledge any personal responsibility.
But the attacks on his own staff have sharpened in recent weeks, and he has suggested to confidants that he has few people at his side he can count on, according to sources.
Coinciding with the heated debate over tariffs, Mr Trump's communications director Hope Hicks, one of his closest and most devoted aides, announced her resignation last week, leaving a glaring vacancy in the informal cadre of Trump loyalists in the White House.
Turnover after just over a year in office is nothing new, but Mr Trump's administration has churned through staff at a dizzying pace since taking office last January, and allies are worried the situation could descend into a free-fall.