Judge Ketanji Brown Jackson at her Senate Confirmation Hearing.

WASHINGTON—The Senate voted 53-47 to confirm Judge Ketanji Brown Jackson as the 116th Supreme Court justice on Thursday, making history in diversifying the bench while leaving unchanged the conservative dominance of a court preparing to tackle gay rights, environmental regulations and race in college admissions.

Judge Jackson, 51 years old, will be the first Black woman to join the Supreme Court, fulfilling a pledge made by President Biden at a pivotal moment in the Democratic presidential race, and her confirmation was celebrated as a groundbreaking moment by backers as well as some detractors. Vice President Kamala Harris presided at the vote.