Amy Coney Barrett, a federal appeals court judge from Indiana, was confirmed Monday to the Supreme Court, with a swearing-in shortly thereafter.
Republicans, overpowering Democrats, confirmed Barrett to the Supreme Court by a vote of 52-48, securing U.S. President Donald Trump's nominee days before the 3 November presidential election.
Only one Republican choose not to vote for Barrett, Susan Collins of Maine, who was opposed to the confirmation.
Barrett, who became the 115th justice to the nation’s highest court, administered the Constitutional Oath before a crowd of about 200.
"This is a momentous day for America," Trump said at the swearing-in event, on the South Lawn, at the White House.
On her part, Justice Barrett stated that it is a privilege to be asked to serve her country in this office.
"I stand here tonight truly honored and humbled. Thanks also to the Senate giving its consent to my appointment. I am grateful for the confidence you have expressed in me and I pledge to you and to the American people that I will discharge my duties to the very best of my ability," she added.
Barrett is expected to take the judicial oath, administered by Chief Justice John Roberts, in a private ceremony on Tuesday, at the court to begin participating in proceedings.
She will fill the vacancy left by the liberal icon Justice Ruth Bader Ginsburg, who died in September after her battle with cancer.
President Trump announced his nominee in September and stated that she needed to be in place before the election.
Democrats wanted a confirmation after the elections. With no real power to stop the vote, Democrats had argued on Sunday that the winner of the presidential election should choose the nominee to fill the vacancy, left by Ginsburg.
This step marks a major political victory for Trump, just 7 days before the presidential election.