White House communications director Anthony Scaramucci has been fired after fewer than 10 days in the post.
The former Wall Street financier had drawn criticism after calling a reporter to give a profanity-laced tirade against his colleagues.
Mr Trump's chief of staff Reince Priebus and spokesman Sean Spicer both left their posts with his appointment.
The decision was made by Mr Trump's new chief of staff, Gen John Kelly, who was sworn in on Monday.
The president was also unhappy with Mr Scaramucci's performance, the White House confirmed.
Mr Trump's spokeswoman, Sarah Sanders, said the president thought Mr Scaramucci's comments to the reporter "were inappropriate for a person in that position".
He has not been moved to another White House role, she added.
Mr Trump had tweeted in the morning about job and wage figures, and insisted there is "No WH chaos", referring to reports about fighting among White House staff.
Gen Kelly, who had formerly served as secretary of homeland security, was sworn in on Monday morning at the White House.
A great night in W Va. we have great momentum. pic.twitter.com/2Cb4OBhsMf— Anthony Scaramucci (@Scaramucci) July 25, 2017
By Anthony Zurcher, BBC News, Washington
Staff in this White House have the job life expectancy of mayflies. Only 10 days ago, Mr Scaramucci burst on to the scene as the fast-talking New Yorker whose fanatical devotion to the president was matched only by his distaste for the established order.
Although his job tenure was short, he managed to do a lot of order-disrupting. Press Secretary Sean Spicer resigned to give Mr Scaramucci a "clean slate". Then, like a heat-seeking missile powered by foul language, Mr Scaramucci went after Reince Priebus, who was unceremoniously cashiered on Friday.
Now it is Mr Scaramucci's turn to wipe down the slate.
If Mr Scaramucci's exit was indeed orchestrated by John Kelly, it could be an indication that the former general is quickly asserting control over what has been a rancorous White House.
Perhaps it is the first sign of order being established, even if the brevity of Mr Scaramucci's tenure - he wasn't officially set to begin until 15 August - will be a short-term embarrassment for the president.
Then again, it could be that the pace of change is quickening as the Trump administration approaches the centre of the vortex. Only time will tell.
The resignation of Reince Priebus came on Friday after Mr Scaramucci posted and then deleted a tweet which many interpreted as an accusation and a threat against Mr Priebus.
During the on-the-record phone call, he also made vulgar statements about chief strategist Steve Bannon.
He also pledged to fire every member of the communications team, as part of his crusade against "leakers".
Mr Scaramucci also called a reporter to attack Mr Priebus as a "paranoid schizophrenic" and accuse him of leaking information to the media.