Since becoming America’s top military officer last year, Air Force Gen. Charles Q. Brown Jr. has hewed to a cautious tack: keeping his views largely to himself, publicly deferring to elected leaders on pressing security questions, and attempting to steer clear of the polarized politics consuming the nation at large.

But Brown was thrust into the heart of a brewing storm Tuesday when President-elect Donald Trump nominated Pete Hegseth, an Army veteran and Fox News host, to become defense secretary, days after Hegseth suggested firing Brown and other senior officers over what he described as a “woke” agenda undermining U.S. military strength. As chairman of the Joint Chiefs of Staff, Brown serves as chief military adviser to both the president and the Pentagon chief.

Trump’s selection of Hegseth — who rose to prominence among Trump-aligned conservatives decrying the dangers of Pentagon “wokeism” and advocating defiance of long-standing military norms — sharply intensifies the challenges facing Brown in the wake of Trump’s Nov. 5 victory, as the general must navigate a highly charged presidential transition and shepherd 1.3 million active-duty troops into a new era while staring down a possible dismissal by his incoming boss.

The potential for a high-profile confrontation between the Pentagon’s two most senior leaders — one a telegenic political appointee, the other a circumspect career soldier — further challenges the military’s fraying status as a trusted, apolitical American institution. Polls show that public confidence in the military, intended to act as a national ballast amid shifting political currents, has fallen to its lowest level in decades.

Kori Schake, a senior fellow at the American Enterprise Institute, cautioned that injecting politics into the management of military issues — even for those who agree with the reasons for doing so — would accelerate that erosion of trust.

“The best course for him is to continue doing what he thinks serves the best interests of the country, whether that keeps him in his job or gets him fired,” Schake said of the general.

Brown, who declined to comment for this article, has not spoken publicly about the comments by Trump or Hegseth.

The Trump campaign did not immediately respond to a request for comment.

A former F-16 pilot, Brown ascended to the top military job in September 2023 with an extensive leadership record, having served as deputy head of U.S. Central Command and chief of U.S. air forces in the Middle East as the military conducted a massive air campaign against the Islamic State. He then commanded air forces in the Pacific before being tapped by Trump as Air Force chief of staff in 2020.

During Brown’s swearing-in ceremony in the Oval Office that year, Trump praised the general, calling him “a great gentleman, a great man.”

Following a 2017 decision by Congress to extend the chairman’s term from two to four years, an attempt to ensure security continuity across administrations, Brown is expected to remain in office until 2027. As a candidate to return to the White House, however, Trump drew a distinction between fighting and “woke” generals, vowing to clear out the latter.

A self-labeled introvert, Brown is described by associates as studious and reserved, often last to speak in a group but concise and direct when he does. Unlike his predecessor, the voluble Army Gen. Mark A. Milley, who was known to regale others with historical lessons and personal stories for hours at a time, Brown typically shares little.

A stickler for schedule and process, he gained wider notice during a moment of national reckoning over race when, following the police killing of George Floyd, he spoke in raw, emotional terms about his experience as a Black man in the U.S. military. While both Brown and Defense Secretary Lloyd Austin are African American, the military’s upper ranks have historically been dominated by White men. Brown served as the country’s first African American Air Force chief and is only the second Black chairman of the Joint Chiefs.

During his confirmation hearing in 2023, Brown faced pressure over the military’s attempts to diversify its ranks and elevate minority personnel, which critics say has undercut military effectiveness and fueled a major recruitment crisis. That included questioning over a 2022 Air Force memo outlining goals for broadening the racial, ethnic and gender composition of Air Force and Space Force candidates.

But Brown has sought to push back on the notion that he supports lowering standards, instead underscoring his backing for merit-based advancement and highlighting his own drive to excel across any demographic group.

“When I put my helmet on and put that visor down and get in that F-16, you don’t know who I am. You don’t really care. You just want to make sure I’m getting the job done,” Brown said this fall. “And that’s what we believe about bringing people into our service.”

The Biden administration has described critics’ emphasis on military efforts to foster diversity as distorted and dishonest. Army leaders have noted that recruits receive just one hour of equal-opportunity instruction during basic training, compared with 92 hours of rifle marksmanship instruction.

In the months leading up to this moment, Brown’s cautious style has mirrored that embraced by retired Gen. Joseph F. Dunford Jr. ahead of the 2016 election, when the then-chairman of the Joint Chiefs rigorously avoided comment on issues being debated by Hillary Clinton and Trump, then a norm-busting newcomer, even when they fell squarely in the military sphere, like the relevance of the NATO alliance. After Trump defeated Clinton, that discipline well served Dunford, who went on to advise the president until the general’s retirement in 2019.

Any chairman preparing to serve a new president must try to maintain distance from politics and ensure they will be viewed as representing the uniformed ranks, rather than the outgoing leader, according to a former military official who advised a previous chairman’s presidential transition.

“He’s got to be able to go into that room and be seen as a credible voice for the military,” the former official said, speaking like some others on the condition of anonymity to discuss this transition. “And if he’s not, he can’t do his job effectively.”

As a senior adviser to the second Trump administration, Brown and his subordinates will have to adapt to their new political leaders’ priorities and goals. The new administration is expected to shift course on the war in Ukraine, voice more categorical support for Israel in its battles against Iranian-linked militants, and potentially take a harder line against Tehran itself.

They will also have to adjust to the incoming administration’s style. During Trump’s previous term, military leaders were often caught off guard by unexpected policy pronouncements made on social media or statements by the president challenging long-held security norms. Eventually officers learned to disregard Twitter pronouncements until they resulted in written orders.

Trump’s previous chairmen, Dunford and Milley, learned to navigate the president’s unpredictable communication style and his seeming interest in dominating the public discourse in Washington. Sometimes that meant waiting to make public pronouncements while traveling overseas rather than doing so in Washington.

“If we were in D.C., the president was the official voice,” the former military official said. “We understood that his voice must be the most prominent when discussing military matters.”

Dan Lamothe contributed to this report.