Sarah Huckabee Sanders will become the new press secretary, with Mr Scaramucci assuming the more backroom role of communications chief.
When Trump informed Spicer that he would be reporting to Scaramucci, the press secretary voiced his objections, according to The New York Times.
The White House had been without a communications director since May when Mike Dubke resigned from the role.
'I just thought it was in the best interest of our communications department, of our press organization, to not have too many cooks in the kitchen, ' Spicer said.
Speaking Friday, Spicer said Trump didn't want him to resign.
Spicer himself addressed the portrayal in a post-resignation interview with Fox News' Sean Hannity. The Friend of Trump reminded Trump's good little soldier of President Donald Trump's stated position on Saturday Night Live, asking Spicer, "Was Saturday Night Live amusing?"
Priebus, an ally of Spicer's who worked with him at the Republican National Committee, praised the outgoing press secretary and acknowledged the difficulty of the job was not only related to handling pesky reporters. Spicer's deputy, will succeed him.
However, during the Friday's briefing, Scaramucci apologized for the remarks, calling them "one of the biggest mistakes that I made because I was an unexperienced person in the world of politics".
"This was the largest audience to ever witness an inauguration, period", Spicer said in an intense statement to the press. I think when it's amusing, it's amusing.
Before Scaramucci endorsed Trump, the investment-firm founder backed GOP candidates Scott Walker and Jeb Bush, reports Business Insider. "That was three minutes of my life, he's never forgotten it, you've never forgotten it, but I hope someday, Mr. President, you will forget it".
Scaramucci described his relationship with White House Chief of Staff Reince Priebus as a brotherly one in which they rough each other up but are good friends, Brennan reported.
Spicer, the father of two, announced on Twitter, that it has been "an honor and pleasure" to serve under the Trump administration.