WILMINGTON, Del. — President-elect Joe Biden plans to tap retired Gen. Lloyd J. Austin III to be secretary of defense, according to three officials familiar with the decision. If confirmed, Austin would be the first Black Pentagon chief.

Austin, 67, rose to become a four-star general in the Army and retired in 2016 as the chief of U.S. Central Command, a role from which he oversaw U.S. military operations across the Middle East for three years. During his tenure there, he presided over the U.S.-led military intervention to stop the rise of the Islamic State, which began seizing cities in Iraq in 2014.

The early days of the campaign against the Islamic State were marked by airstrikes and U.S. efforts to build a coalition to roll back the militant group’s gains. It also had some embarrassments, including a failed $500 million effort to train Syrian rebels to fight the Islamic State.

The three officials spoke on the condition of anonymity to disclose a decision that has not been made public. A spokesman for the transition declined to comment. Earlier Monday, as Biden left the Queen theater in Wilmington, where he had held meetings with transition advisers, he told reporters that he would unveil his pick for secretary of defense on Friday.

Austin’s selection will prompt a congressional debate over whether enough lawmakers would support a waiver from a law that mandates any service member must be out of uniform for at least seven years before being eligible to serve as defense secretary. The law is meant to ensure civilian control of the military.

The Trump administration obtained a similar waiver for Jim Mattis, a retired Marine Corps general, to serve as defense secretary, but it came at a time when many Republicans had taken themselves out of the running for the job by openly criticizing Donald Trump when he was a presidential candidate.

Austin’s biography was particularly appealing to Biden, according to a person familiar with the decision who spoke on the condition of anonymity to disclose deliberations.

Biden has had a personal relationship with Austin and even attended the general’s 2010 change-of-command ceremony when Austin took over in Iraq. Biden, whose portfolio as vice president included Iraq, worked with him closely during the Obama administration.

Austin oversaw not only the operations against the Islamic State but also the withdrawal of U.S. combat forces in Iraq — a massive logistical undertaking that could be significant as the United States endeavors to distribute a coronavirus vaccine, according to the person who requested anonymity to discuss internal deliberations.

Biden also was impressed by Austin’s barrier-breaking career in the military, which spanned about four decades and included being the first Black officer to command a division in combat and the first Black officer to oversee a theater of war.

On a more personal note, Austin also has had experience comforting Gold Star families and understands the human cost of war, which Biden feels is important, the person said. Biden offered the position to Austin on Sunday, and Austin accepted it that day.

But the news that he had been selected to lead the Pentagon prompted a swift pushback on Monday evening. Politico was the first to report on Biden’s decision to choose Austin.

It was Biden’s own party that most vociferously objected to waiving the rule against recent military leaders assuming control of the Pentagon.

Mattis received a waiver with an 81-to-17 vote in the Senate and a 268-to-151 vote in the House, but the majority of those opposing him were Democrats or independents who caucus with them. They included Sens. Tammy Duckworth (Ill.), Elizabeth Warren (Mass.), Kirsten Gillibrand (N.Y.), Cory Booker (N.J.) and Bernie Sanders (I-Vt.). Many House Democrats who rejected Mattis’s waiver were upset that the Pentagon nominee did not testify before their chamber in advance.

Some influential Democrats who supported the waiver for Mattis emphasized at the time that they would not do so again — underscoring, in their view, the vital importance of civilian control of the military.

“Waiving the law should happen no more than once in a generation,” Sen. Jack Reed (R.I.), the top Democrat on the Armed Services Committee, said in 2017. “Therefore, I will not support a waiver for future nominees, nor will I support any effort to water down or repeal the statute in the future.”

In an opinion piece in the New York Times on Monday, Jim Golby, a retired Army officer who studies civil-military relations, argued that although Austin was a fine public servant, appointing another retired general to become defense secretary would not help the Pentagon return to normal after the Trump era.

“Even if a retired general like Mr. Mattis was the right person for the Trump era, that era is over,” Golby wrote.

Although Austin has deep experience in the Middle East, and Iraq especially, he is less seasoned when it comes to China, which the Pentagon under the Trump administration named as its primary security concern.

As a general, he was seen as willing to work within parameters that the White House set for him, even when operations were not going well. He also was viewed as intensely private, rarely doing news interviews and struggling at times during congressional hearings.

In one memorable exchange in 2015, then-Senate Armed Services Committee Chairman John McCain (R-Ariz.) pressed Austin on how operations against the Islamic State were going, and called them an “abject failure.” At the time, migrants were fleeing Syria, and the militants had control of Mosul and other major cities in Iraq.

“General, what you’re telling us is that everything is fine as we see hundreds of thousands of refugees leave and flood Europe,” he said. “I’ve never seen a hearing that is as divorced from the reality of every outside expert and what you are saying.”

The potential history-making nomination of Austin also comes at a time when the Biden administration is facing significant pressure from multiple constituencies to put together a Cabinet with considerable racial diversity.

Biden has already announced two Black women — veteran U.S. diplomat Linda Thomas-Greenfield and Princeton labor economist Cecilia Rouse — as his choices for U.S. ambassador to the United Nations and chair of the Council of Economic Advisers, respectively. Under Trump, those jobs were lowered to a non-Cabinet rank, but Biden has said he will restore both positions to Cabinet level.

The president-elect also has announced two Latinos for high-profile Cabinet slots — Xavier Becerra for secretary of health and human services and Alejandro Mayorkas to lead the Department of Homeland Security. Biden also plans to nominate Neera Tanden, an Indian American who leads the liberal think tank Center for American Progress, as his director of the Office of Management and Budget.

Biden and Vice President-elect Kamala D. Harris are scheduled to meet in Wilmington on Tuesday afternoon with several civil rights leaders, who had planned to discuss the incoming administration’s personnel choices among other priorities. The meeting was set before Austin’s selection became known.

For weeks, it appeared Michèle Flournoy, a former top Pentagon official in the Obama administration, was the favorite to be named Biden’s defense secretary. She would have made history in her own right as the first woman to lead the Pentagon.

But in recent days, Flournoy had come under criticism from antiwar groups for her support for a bigger defense budget, a hawkish posture toward China, and support for military intervention in Libya and Syria.

A group of antiwar activists, including actress Jane Fonda and more than a dozen others, wrote a letter to Biden on Monday opposing her nomination, saying that although she would “break the Pentagon glass ceiling,” she embodies a “pro-war orientation that we oppose.”

Some liberal groups, meanwhile, came to view Austin as the least objectionable option of a list of hawkish candidates with extensive ties to defense contractors.

“Progressives should be encouraged that Austin was criticized from the right for his desire to avoid civilian casualties in his air campaign against ISIS,” said Erik Sperling, executive director of Just Foreign Policy, a dovish foreign policy organization based in Washington. “Austin’s approach rightly tracked the reluctance of President Obama and other senior civilian officials to re-engage militarily in the Middle East.”

Karoun Demirjian contributed to this report.