President Biden is expected to nominate the chief of staff of the Air Force, Gen. Charles "CQ" Brown Jr., to serve as chairman of the Joint Chiefs of Staff, choosing a deeply seasoned officer and fighter pilot with experience commanding troops in the Middle East and the Pacific to be his next senior military adviser, according to three people familiar with the matter.

If confirmed by the Senate, Brown would replace Gen. Mark A. Milley, whose tenure as chairman coincided with a tumultuous period in history, one that included the U.S. Capitol attack, the deadly evacuation of Afghanistan, and the American-led effort to train and arm Ukraine as it fights invading Russian forces. The pugnacious Milley clashed frequently - and sometimes publicly - with the man who tapped him for the assignment: President Donald Trump.

Biden zeroed in on Brown as his preferred candidate after also interviewing Gen. David H. Berger, the commandant of the Marine Corps. Berger has recently told colleagues that he intends to retire, a senior military official familiar with the matter said. Like others, this person spoke on the condition of anonymity to discuss the high-profile personnel move. A Marine Corps spokesman could not immediately be reached for comment.

It was not immediately clear when Biden intends to make an announcement. The National Security Council said in a statement: "When President Biden makes a final decision, he will inform the person selected and then announce it publicly. That hasn't happened yet."

News of Brown's expected selection was reported earlier by Politico.

The next chairman's portfolio will include regularly interfacing with Ukraine's senior military leaders and U.S. allies with a stake in the war, preparing the United States for potential conflict with China, and attempting to steer the military, with its nonpartisan tradition, through the nation's frequently toxic politics. American confidence in the military has plummeted in recent years, according to several surveys, drawing concern from Defense Secretary Lloyd Austin and other senior defense officials.

Brown became the first African American to lead a branch of service, and he acknowledged when taking the job that doing so came with "immense expectations." If confirmed as chairman, he will become the second African American to serve as the Pentagon's top military officer, following in the footsteps of Gen. Colin Powell, who ascended to the job in 1989 after serving as President Ronald Reagan's national security adviser. It would mark the first time the Pentagon's top two jobs are held by African Americans.

Even keeled and affable, Brown has led the Air Force since June 2020. In that time, he has warned that the service must accelerate how quickly it modernizes or risk losing its superiority. To that end, he has pressed for the retirement of aging warplanes in favor of more advanced aircraft, stressing that U.S. dominance in the sky may not apply in the future. He has also prioritized improving working conditions for Air Force personnel, and put an emphasis on diversity and racial justice.

"I want these things to be enduring well after I'm gone - if someone wants to look back and say CQ Brown was part of that, fine - but I just want to make our Air Force as capable as possible," Brown said during a recent appearance at the Brookings Institution.

While awaiting his confirmation to become Air Force chief of staff, Brown memorably released a video describing his experience as a Black man in the military after the police killing of George Floyd. He said in it that he was aware of the "immense expectations" that came with his historic promotion, "particularly through the lens of current events plaguing our nation."

Brown served previously as the top U.S. Air Force officer in the Pacific, and before that oversaw U.S. forces in the Middle East as deputy commander of U.S. Central Command and commander of Air Forces Central Command.

The son of a retired Army colonel, he split his childhood between California, Virginia, Oklahoma, Germany and Texas, and attended Texas Tech University on a Reserve Officers' Training Corps scholarship.