Supreme Court Justice Stephen Breyer officially announced his retirement on Jan. 27, a day after the news was leaked and widely reported.
Breyer said he assumes his successor will be nominated by Biden and confirmed by the Senate by then.
"I enormously appreciate the privilege of serving as part of the federal judicial system—nearly 14 years as a Court of Appeals Judge and nearly 28 years as a Member of the Supreme Court," the Clinton nominee wrote in the two-paragraph document.
"I have found the work challenging and meaningful. My relations with each of my colleagues have been warm and friendly. Throughout, I have been aware of the great honor of participating as a judge in the effort to maintain our Constitution and the rule of law."
Biden, a Democrat, who as a senator helped get Breyer confirmed in the 1990s, called the day "bittersweet," while championing what he called Breyer's "distinguished career."
Breyer "gave faith to the notion that the law exists to help the people," he said in prepared remarks in front of a crowd in the Roosevelt Room of the White House.
Breyer said he's found it meaningful sitting on the bench and hearing cases presented by all sorts of people, calling it "a kind of miracle when you sit there and see all those people in front of you, people that are so different in what they think and yet they have decided to solve their major differences under law."
Recalling talks to classes, he said when students "get too cynical," he'll tell them to "go look at what happens in countries that don't do that."
"People have come to accept this Constitution and have come to accept the rule of law," he said in remarks delivered after Biden spoke, holding up a copy of the U.S. Constitution.
Breyer's retirement announcement was upstaged a day earlier by Senate Majority Leader Chuck Schumer (D-N.Y.), who told reporters of the plans. Schumer was one of many Democrats who directly or indirectly pressured Breyer, the court's oldest justice, to step down.
"As always, Senate Democrats stand ready to expeditiously fill any potential vacancies on the Supreme Court should they arise," Schumer wrote in a letter to colleagues last year.
Schumer presides over a divided Senate, comprising 50 Republicans and 50 Democrats or nominal independents who often vote with the Democrats. Vice President Kamala Harris, a Democrat, can break ties as president of the upper chamber.
A majority vote would confirm the nominee.
Some Republicans have called for a slower process.
"I felt that the timetable for the last nominee was too compressed. This time, there is no need for any rush. We can take our time, have hearings, go through the process, which is a very important one. It is a lifetime appointment, after all," Sen. Susan Collins (R-Maine) told reporters in Washington.
While campaigning for president, Biden vowed to nominate a black woman should a Supreme Court vacancy arise during his presidency and reiterated that position at the White House.
He said the woman "will be somebody with extraordinary qualifications." He said he hasn't made a choice yet.
Breyer, who joined the court on Aug. 3, 1994, has seen the number of judges nominated by Democratic presidents dwindle in recent years. Former President Donald Trump got three SCOTUS nominations, filling seats left open by the deaths of justices Antonin Scalia and Ruth Bader Ginsburg, and the retirement of Justice Anthony Kennedy.