His path to confirmation was met with enormous opposition from Democrats and left-wing groups - which intensified after Christine Blasey Ford accused him of sexually assaulting her, allegations Kavanaugh denied and which the Federal Bureau of Investigation (FBI) found to be uncorroborated. He had denied her allegation.
It seemed like business as usual in the ornate courtroom, three days after Kavanaugh was confirmed by the Republican-led Senate despite being accused of sexual assault by a university professor named Christine Blasey Ford.
Kavanaugh is the second justice Trump has successfully nominated to the Supreme Court, following the confirmation a year ago of Neil Gorsuch to the seat left by the late Antonin Scalia.
Those who were there held signs saying "We will not forget" and "We do not consent", following the acrimonious fight that culminated in Kavanaugh's 50-48 Senate confirmation Saturday.
"I've always been told it's the biggest thing a president can do and I can understand that", he said Monday upon returning from the brief Florida trip.
Mr Kavanaugh was 'caught up in a hoax set up by the Democrats, ' Mr Trump said.
The other eight justices are all in attendance for Monday's swearing-in, which is entirely ceremonial. Lacy had been working at the White House in support of Kavanaugh's nomination.
Kavanaugh did make note of the battle that surrounded his confirmation, pointing out the senators and White House aides, including White House counsel Donald McGahn, who helped push his nomination through. Fred Schilling/Supreme Court of the United States.
The newest justice's wife and two daughters were in seats reserved for justices' guests, along with retired Justice Anthony Kennedy.
As a woman and mother in Maine, I'm very disappointed in Susans Collins' vote to confirm Judge Brett Kavanaugh to the Supreme Court ("Collins says she will vote to confirm Kavanaugh to Supreme Court", Oct. 5).
Later, in Orlando, he called Kavanaugh "a flawless person". McConnell said that the tactics failed to sway Senate Republicans. "I think, frankly, we are just less than a month away from an election".
Oh, who are we kidding?
ActBlue - an online fundraising platform for Democrats - raised almost $10 million on October 5 - the day the Senate held a procedural vote on moving Kavanaugh's nomination forward - and another $9 million on October 6, the day the upper chamber formally confirmed him. Pat Leahy, D-Vt., said in a tweet.
114 Justices (including Kavanaugh) have been appointed to the Bench since the Supreme Court was established in 1789.
Ford accused Kavanaugh of pinning her to a bed, groping her and covering her mouth when she screamed during a teenage party in the 1980s.
"It was all made up, it was fabricated and it's a disgrace", he said.
Democrats have said that an FBI investigation into the allegations that Trump ordered was too limited in scope to be useful.
National Republicans believe frequent trips from Trump should be able to accentuate those state's natural political bent and overcome a national atmosphere that appears to favor Democrats.
Initially Democrats had been favored to take control of the House of Representatives and - in early September - were seen as having a decent chance of taking the Senate as well.
"I think a lot of Democrats are going to vote Republican", he said. "This country would end up being Venezuela". He took his oaths of office in a private ceremony at the Supreme Court on Saturday evening.
There are two exceptions: Justices Sonia Sotomayor and Elena Kagan. "President, you will not fill the Supreme Court vacancy, '" McConnell famously said in August 2016.
108 Justices - 95% - have been white men. Both men testified about their respect for Supreme Court precedent, though Gorsuch already has been in the majority to overrule four high-court rulings.