A week after a communications team shake-up at the White House, President Donald Trump announced he was replacing his chief of staff with his homeland security secretary—leaving a key Cabinet position to fill.

“Reince is a good man. John Kelly will do a fantastic job,” @POTUS says.

Just before 5 p.m. Friday, Trump tweeted that Homeland Security Secretary John Kelly would replace Reince Priebus as White House chief of staff.

Priebus reportedly opposed the hiring of Anthony Scaramucci as White House communications director. Scaramucci also disparaged Priebus, according to The New Yorker, and said he and Priebus were brothers like “Cain and Abel” in a CNN interview.

I am pleased to inform you that I have just named General/Secretary John F Kelly as White House Chief of Staff. He is a Great American…. — Donald J. Trump (@realDonaldTrump) July 28, 2017

…and a Great Leader. John has also done a spectacular job at Homeland Security. He has been a true star of my Administration — Donald J. Trump (@realDonaldTrump) July 28, 2017

After returning to Andrews Air Force Base from a visit to New York, Trump briefly spoke to reporters shouting questions.

“Reince is a good man. John Kelly will do a fantastic job,” the president said. “General Kelly has been a star, done an incredible job thus far, respected by everybody. He’s a great great American. Reince is a good man.”

Before taking on the White House role, Priebus had been chairman of the Republican National Committee since 2011. After Trump secured the Republican presidential nomination in 2016, upsetting many movement conservatives and establishment Republicans alike, Priebus and the RNC got behind the nominee.

“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,” Priebus said in statement released by the White House shortly before 6:30 p.m. “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.”

Last Friday, after Scaramucci took over as communications director, he announced that Sarah Huckabee Sanders would be the new press secretary, replacing Sean Spicer. At the RNC, Spicer was the top communications official under Priebus.

Sanders said the change in chief of staff had nothing to with Scaramucci.

“We all serve at the pleasure of the president,” Sanders told reporters in a late afternoon press gaggle outside her office. “The conversations about this started with the president and Reince about two weeks ago, in terms of timing.”

Kelly, 67, a retired Marine general, previously served as a congressional liaison for the Marines and special assistant to the supreme allied commander in Europe. He became a brigadier general in 2002, and served three tours in Iraq.

After being promoted to lieutenant general, he became the senior military assistant for two secretaries of defense, Robert Gates and Leon Panetta, the latter one of President Bill Clinton’s chiefs of staff.

Kelly earned a fourth star and took command of United States Southern Command, a position he held until January 2016.

The transition from a military career to a political role is one Kelly can handle, said James Jay Carafano, vice president for the Davis Institute for National Security and Foreign Policy at The Heritage Foundation.

“The White House chief of staff job has a powerful political dimension to it,” Carafano said in a prepared statement. “This is a skill set that Kelly would have to learn on the job. It is not that he doesn’t understand the politics. Good strategic military leaders understand how the politics influences military action and vice versa.”

Carafano added of military leaders: