But it had been obvious for some time from news reports that Priebus seemed to be on thin ice in the Trump White House.
The news broke as the President returned to Washington from an event on Long Island, in New York.
Priebus had been on the trip, but according to the White House Pool report, the car he was riding in was separated from the President's motorcade, as Mr. Trump headed back to the White House.
A week ago, Anthony Scaramucci was unexpectedly brought in as White House Communications Director, prompting the resignation of Press Secretary Sean Spicer.
That brought immediate questions about the ability of Scaramucci and Priebus to co-exist inside the Trump White House - and it took just a week for Priebus to be on his way out.
Earlier this week, Scaramucci even seemed to accuse Priebus of leaking material against him, reinforcing the palace intrigue involving the two men inside the Trump orbit.
On Thursday, House Speaker Paul Ryan - a fellow Wisconsin resident like Priebus - had downplayed the idea that Priebus was in trouble.
Priebus had been the head of the Republican National Committee during Mr. Trump's ascendancy in the GOP primaries, moving over to help with the campaign for November. He then was tapped as White House Chief of Staff, despite some concerns from some Trump backers, who saw Priebus as too much of the GOP Establishment.
One thing that Priebus had was good relations with the Congress, which provided a vital lifeline from Capitol Hill to the White House.
"Reince Priebus did a good job as chief of staff," said Sen. James Lankford (R-OK). "His expertise and relationships with Congress benefited the White House in many ways."
As for Kelly, he is well respected in the Congress as well, though he has ruffled some feathers with tough verbal rebukes for members of Congress who did not like some of his policy choices on immigration law enforcement.
His replacement will have to go through Senate confirmation hearings later this year.
Priebus issued this statement soon after his departure was announced by the President:
"It has been one of the greatest honors of my life to serve this President and our country. I want to thank the President for giving me this very special opportunity. I will continue to serve as a strong supporter of the President's agenda and policies. I can't think of a better person than General John Kelly to succeed me and I wish him God's blessings and great success."
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