Supreme Court Justice Stephen Breyer, the most senior member of the U.S. Supreme Court's liberal wing, said he will officially step down from the bench at noon on Thursday, and the court announced he will then swear in his former law clerk -- Ketanji Brown Jackson -- to take his place on the bench, becoming the nation's first Black female justice.

"It has been my great honor to participate as a judge in the effort to maintain our Constitution and the Rule of Law," Breyer wrote in a letter to President Joe Biden dated Wednesday.

Breyer's retirement fulfills the wish of Democrats who lobbied for his exit to make way for Biden's first nominee to the court

Jackson will take both her oaths at noon -- Chief Justice John Roberts administering the Constitutional Oath and Justice Breyer delivering the Judicial Oath. Her presence will mark the first time four women will be on the Supreme Court at the same time.

Progressive activists had imposed unprecedented public pressure on Breyer, who was nominated in 1994 by President Bill Clinton, to retire. Breyer was first appointed to the federal bench in 1980 by President Jimmy Carter, going on to serve 13 years as an appellate judge until Clinton elevated him to replace Justice Harry Blackmun on the Supreme Court in 1994. The Senate confirmed him 87-9.

Last term, Breyer authored major opinions upholding the Affordable Care Act, affirming free speech rights of students off-campus and resolving a multi-billion dollar copyright dispute between two titans of American technology, Google and Oracle.