Joe Biden is expected to nominate federal appeals court Judge Ketanji Brown Jackson to the Supreme Court, which would make her the first black woman selected to serve on a court that once declared her race unworthy of citizenship and endorsed segregation.

The president is set to deliver on a campaign promise to make the historic appointment and to further diversify a court that was made up entirely of white men for almost two centuries.

He has chosen a lawyer who would be the high court’s first former public defender, though she also possesses the elite legal background of other justices.

Ms Jackson would be the current court’s second black justice – after Justice Clarence Thomas, a conservative – and just the third in history.

She would also be only the sixth woman to serve on the court, and her confirmation would mean that for the first time four women would sit on the nine-member court.

The three current women include the court’s first Latina, Justice Sonia Sotomayor.

Ms Jackson would join the liberal minority of a conservative-dominated court that is weighing cutbacks to abortion rights and will be considering ending affirmative action in college admissions and restricting voting rights efforts to increase minority representation.

Mr Biden is filling the seat that will be vacated by Justice Stephen Breyer, 83, who is retiring at the end of the term this summer.

Ms Jackson, 51, worked as one of Mr Breyer’s law clerks early in her legal career. She attended Harvard as an undergraduate and for law school, and served on the US Sentencing Commission, the agency that develops federal sentencing policy, before becoming a federal judge in 2013.

Her nomination is subject to confirmation by the Senate, where Democrats hold the majority by a razor-thin 50-50 margin with vice president Kamala Harris as the tie-breaker.

Party leaders have promised swift but deliberate consideration of the president’s nominee.

The next justice will replace one of the more liberal justices, so she would not tip the balance of the court, which now leans 6-3 in favour of conservatives.

Senate Judiciary Committee chairman Dick Durbin has said he wants the Senate to move quickly on the nomination, and senators have set a goal of confirmation by mid-April.

But that timeline could be complicated by a number of things, including developments between Russia and Ukraine and the extended absence of Democratic senator Ben Ray Lujan, who suffered a stroke last month and is out for several weeks. Democrats would need his vote to confirm Mr Biden’s pick if no Republicans support her.

Once the nomination is sent to the Senate, it is up to the Senate Judiciary Committee to vet the nominee and hold confirmation hearings. After the committee approves a nomination, it goes to the Senate floor for a final vote.

Ms Jackson was on the president’s short list as a potential nominee even before Mr Breyer retired.

Mr Biden and his team spent weeks poring over her records, interviewing her friends and family and looking into her background.

She serves on the US Court of Appeals for the District of Columbia Circuit, a position that Mr Biden elevated her to last year from her previous job as a federal trial court judge.

She was confirmed to that post on a 53-44 Senate vote, winning the backing of three Republicans.