By a vote of 50-48, the Senate gave a lifetime job to Kavanaugh, 53, after weeks of fierce debate over sexual violence, alcohol abuse and privilege that convulsed the nation just weeks before the US congressional elections on Nov. 6.
The Senate vote takes the highest US court down a more conservative path for perhaps a generation and is a bitter blow to Democrats already chafing at US Republican control of the White House and both chambers of the US Congress.
Kavanaugh's nomination became an intense personal and political drama when university professor Christine Blasey Ford accused him of sexually assaulting her when they were high school students in a wealthy suburb of Washington in 1982.
Two other women accused him in the media of sexual misconduct in the 1980s.
Kavanaugh fought back hard, denying the accusations in angry and tearful testimony before the Senate Judiciary Committee that was viewed live on television by around 20 million people.
Trump stood by Kavanaugh, a federal appeals court judge with a history of advancing Republican causes, and this week mocked Ford's account of what she says was a drunken attack on her by Kavanaugh when they were teenagers.
Trump, seeking a legacy as the president who put a strongly conservative stamp on the court, said on Saturday before the vote that Kavanaugh would do "great, great" job there.
Democrats said Kavanaugh's partisan defense of himself, in which he said he was victim of a "political hit," was enough itself to disqualify him from the court.
Repeatedly during the Senate debate, Republicans accused Democrats of staging a "smear" campaign against Kavanaugh to prevent a conservative becoming a Supreme Court justice.
The accusations against Kavanaugh energized the #MeToo social media movement that emerged after high-profile accusations of sexual assault and harassment by men in politics, the media and the entertainment industry.
Kavanaugh is expected to be sworn in quickly and will join four liberal justices and four other conservatives as the court, which is expected soon to hear controversial disputes involving abortion, immigration, gay rights and voting rights.
The dispute over Kavanaugh has added fuel to campaigning for the midterm elections in November when Democrats will try to take control of US Congress from the Republicans.