Amy Coney Barrett was confirmed by the Senate by 52 to 48 votes, filling Ruth Bader Ginsburg's seat and transforming the Supreme Court.
The 48-year-old appeals court judge became Donald Trump's third Supreme Court Justice in the face of united Democratic opposition.
Susan Collins of Maine was the only Republican to cross the aisle and vote against Coney Barrett - her re-election is already severely imperiled.
Supreme Court Justice Clarence Thomas will swear in Barrett in a White House ceremony.
The event has a 'large' guest list, a source claimed - eerily similar to the Rose Garden super spreader event used to unveil her as nominee.
Mother of seven, a devout Catholic who is member of charismatic group People of Praise, is likely to be one of the most conservative justices.
She becomes the only mid-western and southern judge, having been born and brought up in New Orleans and living since then in South Bend, Indiana.
Amy Coney Barrett was confirmed to the Supreme Court Monday evening by the Senate in a 52-48 vote - with Republican Susan Collins crossing the aisle to vote against her.
Donald Trump's third nominee was not in the chamber to watch the roll call vote, which allows her to join the eight justices on Tuesday morning, and potentially to decide on cases about voting before the November 3 election.
Senate president pro tempore Chuck Grassley declared her confirmation at 8.06pm to applause from fellow Republicans; outside the Supreme Court conservatives chanted Coney Barrett's name as soon as she was confirmed.
Her confirmation transforms the court to a 6-3 conservative majority and comes after fierce opposition from Democrats, whose presidential nominee Joe Biden has resisted pressure to promise to pack the court if he wins - but who says he will order a commission on reforming the high court.
Before the final vote she was praised by Republican majority leader Mitch McConnell who said: 'By every account, the Supreme Court is getting not just an outstanding lawyer but a fantastic person.
'This is one of the brilliant, admired and well-qualified nominees in our lifetime,' he said.
She will be the only justice confirmed with a law degree from 'any school not named Harvard or Yale.'
McConnell added in an acknowledgment of the controversy over killing Rhth Bader Ginsburg's seat days before the election and in defiance of her dying wish: 'I think we can all acknowledge that both sides in the Senate have sort of parallel oral histories about the last 30 or so years.
'Each side feel the other side struck first and struck worse.'
Democratic leader Chuck Schumer, however, scorned the process which saw Coney Barrett confirmed on the eve of an election when McConnell had stopped even a hearing for Merrick Garland, Barack Obama's nominee, in 2016.
'You may win this vote. And Amy Coney Barrett may become the next Associate Justice of the Supreme Court. But you will never, ever, get your credibility back,' he said to Republicans on the Senate floor.
Democrats had made the nomination before an election the center of their case against her, and highlighted her conservative rulings while a federal appeals court judge.
They had also warned that she may vote down Obamacare, move to overturn Roe v. Wade, which enshrines women's right to choose, and imperil restrictions on gun ownership, but could not stop McConnell's express train to fill the seat before the election.
The 48-year-old becomes the youngest member of the court, and almost certainly one of its most conservative.
But with Collins - whose re-election in Maine next week is already in jeopardy, according to polls - voting against Coney Barrett, she is the only one of Trump's nominees not to have at least one Democratic vote, and the only one with a Republican voting against her.
Justice Clarence Thomas is on the docket to swear in the 7th Circuit appellate judge to the Supreme Court at a White House ceremony.
'Justice Clarence Thomas will administer the official Constitutional Oath to Judge Amy Coney Barrett at the White House tonight,' a senior White House official told The New York Times.
White House chief of staff Mark Meadows sought to assure reporters Monday that the Rose Garden ceremony would include safety precautions, but he did not say whether face coverings would be required.
'We're doing tonight the best we can to encourage as much social distancing as possible,' he said.
The plans had set off alarm bells as it sounds eerily similar to the Rose Garden event last month when Trump announced Barrett's nomination, inviting a whole crowd of aides, advisers, lawmakers and supporters to witness the occasion.
That event sparked a White House outbreak of COVID-19, which infected the president, first lady Melania and their son Barron, as well as about a dozen others within Trump's inner circle.
Not present in the Senate was Mike Pence. Pence announced earlier Monday that he was ditching his plans to attend after Democrats demanded he steer clear of the Capitol as five of his aides tested positive for coronavirus.
The White House, however, is still looking to hold a Rose Garden celebration with a ceremonial swearing in of Barrett either Monday or Tuesday.
Speaking to reporters on the tarmac at Lehigh Valley International Airport in Pennsylvania on Monday, President Donald Trump assured the celebration would be a rather small, 'very nice event.'
On Sunday, the Senate held a procedural vote to advance Barrett's nomination and kicked off 30 hours of debate, which will clear the way for a vote Monday evening.
'This is something to be really proud of and feel good about,' Senate Majority Leader Mitch McConnell said during a rare weekend session.
McConnell lauded that Democrats 'won't be able to do much about this for a long time to come', in contrast to legislative actions, which can be undone with new executive or legislative terms.
Barrett, a 48-year-old appellate judge for the 7th circuit, is a staunch Roman Catholic and life-long conservative. Her personal pro-life views have raised eyebrows among progressives who claim she will dismantle a woman's right to an abortion by working to overturn Roe v. Wade.
She is a member of People of Praise, a small and ultra-conservative charismatic group whose members speak in tongues.
Republicans had painted questions over her faith as an attack on Catholics at large and Democrats had steered clear of the group in their questions to her.
Her lifetime appointment to the highest U.S. court will also drastically change the makeup of the Supreme Court for a generation to come.
The mother of seven – five biological and two adopted from Haiti – has embraced her classification as the 'female Antonin Scalia' and says his jurisprudential practice of 'applying the law as written' will be how she serves.
During the three days of confirmation hearings earlier this month, including a day of opening statements and two days of questioning, Barrett reiterated her stance as a textualist and originalist, stressing this means she would apply the Constitution to cases as it's written and was intended by the drafters.
In the short term, Barrett could help decide election and voting-related issues as the vote on her confirmation comes just over a week before Election Day.
Donald Trump has made it clear he feels the results of the election could end up at the Supreme Court – and with a conservative majority of 6-3 with Barrett seated, it's more likely they would rule in favor of the president.
Also about a week after the election the Supreme Court will take up a case on the Affordable Care Act, which Democrats fear will be overturned if Barrett has anything to say about it.
Amy Coney Barrett is 48, a mother of seven and a brilliant legal mind - and now she is the most divisive Supreme Court Justice in at least a generation and perhaps far longer.
She brings to the Supreme Court a short judicial career, a longer academic one and the hopes of a conservative legal movement that they have a secure 6-3 majority in the high court for now, and a stalwart vote on it for many decades to come.
Coney Barrett's life story makes her the sixth Catholic on the court, keeps the six-three male-female make-up of the bench, and for the first time ever puts on the court someone who openly identifies with the charismatic wing of modern Christianity.
She is also the only one who did not receive an education at Harvard or Yale, and the only mid-western and southern justice, having been born and brought up in Louisiana and spent the rest of her life in Indiana.
Barrett was brought up in Metairie, Louisiana, as a member of charismatic, conservative, Catholic group People of Praise and one of seven children.
Her father, Mike Coney, a former oil company lawyer, has been a leading member for decades. Her attorney-husband, Jesse, 46, whom she met while both were students at Notre Dame University, was also raised in the group.
She had studied for her undergraduate degree at Rhodes College in Memphis, TN, and contemplated further study in English literature but instead decided to study law, going to Notre Dame whose law school has built a reputation as predominantly conservative.
Described by one professor as the best student he had ever had, she went on to be a clerk for Antonin Scalia, the justice who championed originalism as a judicial philosophy.
She had a brief career in private practice but became a law professor at Notre Dame, and married and had seven children.
The visible manifestation of her conservative Catholic beliefs was part of her appeal to political conservatives.
But it has also focused attention on the tiny group, which has just over 2,000 members and which does not represent mainstream Catholicism.
People of Praise is headquartered in Notre Dame's hometown, South Bend, Indiana, and many of its leading members have ties to the university. According to its website, the group has branches in 14 states as well as one in Canada and two in the Caribbean. It runs three Grades 7-through-12 Trinity Schools and one elementary school.
Both— who lives in South Bend — and People of Praise seem to have gone to extraordinary lengths to hide her affiliation. Articles mentioning her were removed from the group's website shortly before she was to be considered for a seat on the Federal Appeals Court in 2017.
Barrett's ties to People of Praise only became public when the New York Times broke the story three weeks after her confirmation hearing as an appeals court judge, but before the committee had voted. The committee eventually split along party lines to confirm her. Three Democrats voted with the Republican majority in the vote in the full Senate.
People of Praise is strongly anti-abortion. It also rejects homosexuality. 'Both are seen as being accepted by human law, but rejected by divine law,' the former member explained.
'Homosexual relationships are taboo, and any LGBTQ inclinations are seen as temptations that must be overcome through prayer. If that fails, the member must lead a life of chastity.'
Even dating is a no-no until a member has 'prayed through their state in life' and decided they are ready to 'marry for the Lord.' If they have not committed themselves to marriage, they must not date.
The group is probably best known for its doctrine that women must obey their husbands in everything, and its system where all men and single women must report to their mentor — called a 'head'. Husbands act as the 'head' for their wives.
The 'heads' have such influence they give direction on who a member should date or even marry, how to raise children, whether to take a new job and where to live.
Until recently the female leader was known as a 'handmaid.' But that title was dropped after the success of the dystopian TV show The Handmaid's Tale and the negative connotations it brought to the title.
Author Margaret Atwood, who wrote the original novel, said it was based on a group that has similar views to People of Praise.
The conservative Catholic beliefs have bled into her public life: she is a former member of the Notre Dame's 'Faculty for Life' and in 2015 signed a letter to the Catholic Church affirming the 'teachings of the Church as truth.'
Among those teachings were the 'value of human life from conception to natural death' and marriage-family values 'founded on the indissoluble commitment of a man and a woman'.
She has previously written that Supreme Court precedents are not sacrosanct. Liberals have taken these comments as a threat to the 1973 Roe v. Wade decision legalizing abortion nationwide.
Barrett wrote that she agrees 'with those who say that a justice's duty is to the Constitution and that it is thus more legitimate for her to enforce her best understanding of the Constitution rather than a precedent she thinks clearly in conflict with it'.
What she said is the distillation of originalism and raises the possibility that she could tear up precedent if she sees it as out of line with the original constiution.
That puts her in sync with Scalia and the Republican senators who voted for her and expect her to rule in line with that for decades to come; it puts her violently at odds with those who do not agree, and puts her on track to be a justice whose presence on the bench is going to divide opinion as long as she remains on it.