President Trump fired the country’s senior military officer as part of an extraordinary Friday night purge at the Pentagon that injected politics into the selection of the nation’s top military leaders.

Gen. Charles Q. Brown Jr., a four-star fighter pilot known as C.Q. who became only the second African American to hold the chairman’s job, is to be replaced by a little-known retired three-star Air Force general, Dan Caine, who endeared himself to the president when they met in Iraq six years ago.

In all, six Pentagon officials were fired, including Adm. Lisa Franchetti, the first woman to lead the Navy; Gen. James Slife, the vice chief of the Air Force; and the top lawyers for the Army, Navy and Air Force.

The decision to fire General Brown, which Mr. Trump announced in a message on Truth Social, reflects the president’s insistence that the military’s leadership is too mired in diversity issues, has lost sight of its role as a combat force to defend the country and is out of step with his “America First” movement.

Joint Chiefs chairmen traditionally remain in place as administrations change, regardless of the president’s political party. But current White House and Pentagon officials said they wanted to appoint their own top leaders.

In a statement, Defense Secretary Pete Hegseth thanked Admiral Franchetti and General Slife “for their service and dedication to our country” and requested nominations for their replacements.

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