Scaramucci is replacing Mike Dubke, who resigned in May only three months after being hired.
Axios first reported the planned hiring of Scaramucci.
In a statement Friday evening, Trump said, “Anthony is a person I have great respect for, and he will be an important addition to this Administration. He has been a great supporter and will now help implement key aspects of our agenda while leading the communications team. We have accomplished so much, and we are being given credit for so little. The good news is the people get it, even if the media doesn’t.”
Scaramucci said in his own statement, “President Trump has accomplished an incredible amount in a short period of time, and I am proud to join his Administration as he continues to deliver for the American people.”
Scaramucci will officially begin his role on Aug. 15, according to the White House. He will report directly to the president.
Senior members of the White House staff, including press secretary Sean Spicer, were unaware that Scaramucci was being considered for the post, even as Trump and first daughter Ivanka Trump were meeting with Scaramucci at the White House Thursday for over an hour to discuss the job.
Scaramucci, 53, is a major Republican donor and was a member of the president's transition team.
Scaramucci has also been vocal about his support of the president's embattled son Donald Trump Jr., tweeting earlier this month, "[Donald Trump Jr.] is a virtuous and honorable man. Virtue means the courage to act with integrity. Don does that everyday. #stopwitchunt"
In January, Scaramucci sold an asset-management business he founded, SkyBridge Capital, as it appeared at the time he would be joining the Trump administration.
The president had said he intended to appoint Scaramucci as director of the White House Office of Public Liaison and Intergovernmental Affairs, but administration officials said soon afterward that Scaramucci would not assume that role and they would seek another position for him. A key issue was that the sale of SkyBridge Capital to a division of a Chinese conglomerate had not yet been completed, meaning it would take months for Scaramucci to be cleared of potential ethics conflicts.
Scaramucci -- who attended Harvard Law School and Tufts University -- made news in June when CNN accepted the resignations of three journalists involved in a retracted story about a supposed investigation into a pre-inaugural meeting between Scaramucci and the head of a Russian investment fund. CNN immediately apologized to Scaramucci. CNN said the story didn't meet its editorial standards and was posted without going through the expected checks and balances for a story of such sensitivity.
The Long Island, New York, native is a frequent guest on Fox News, and previously hosted "Wall Street Week" on the Fox Business Network.