Trump was speaking during a phone interview with Fox News when he made the comments shortly after Justice Kavanaugh was sworn into the Supreme Court.
Despite a slew of sexual misconduct allegations against Mr Kavanaugh – and the hundreds of protesters that descended on Capitol Hill as tensions hit fever pitch – his position was sealed following a vote that ended 50-48 in his favour last weekend.
It was the closest Supreme Court nomination vote in more than a hundred years.
Reacting to the news, Trump told Fox News host Jeanine Pirro that his critics had “overplayed their hand” in their opposition to Kavanaugh.
He said: “I think that they should be held liable.
“I would say they should be held to the highest standard.
“You can’t go around — whether it’s making up stories or making false statements about such an important position — you can’t do that.
“You can destroy somebody’s life.”
He added: “There were many, many false things that were said about a very fine man and would have destroyed his family if this didn’t happen.
“It all came together in the end and people realised it was false accusations, false statements.
“The confirmation was really something very nice.
“He suffered from false statements made against him.
“Things that never happened.”
Speaking at a Kansas campaign rally shortly after Kavanaugh’s confirmation, Trump touted the result as a “tremendous victory”.
The firebrand Republican said: “I stand before you today on the heels of a tremendous victory for our nation, our people and our beloved constitution.”
Justice Kavanaugh has been accused of sexual abuse, as a number of women have come forward to raise allegations of historical misconduct.
But Mr Kavanaugh strenuously denies all charges levelled against him.
The latest sensational testimony was given before a Senate judiciary hearing by Psychology Professor Christine Blasey Ford.
Ms Ford alleges Mr Kavanaugh drunkenly attempted to rape her while his friend, Mark Judge, stood by and watched during a 1982 gathering.
But Republicans, spearheaded by President Trump, have questioned the reliability of Ms Ford’s account.
Responding to the allegations in front of the Senate Judiciary Committee on Thursday September 27, Mr Kavanaugh said Ms Ford and other accusers had “destroyed” his family name.
Trump has stood by his nominee and consistently defended him despite the barrage of allegations and anti-Kavanaugh demonstrations.
The President said: “Well, there were a lot of things happening that weren’t correct, they weren’t true and there were a lot of things that were left unsaid.
“And I thought I had to even the playing field. It was very unfair to the judge, and now I can very nicely say, Justice Kavanaugh.
“It was a very unfair situation. So I evened the playing field. Once I did that, it started to sail through.”
On Saturday, Trump tweeted: “I applaud and congratulate the US Senate for confirming our great nominee, Judge Brett Kavanaugh, to the United States Supreme Court.
“Later today, I will sign his Commission of Appointment, and he will be officially sworn in. Very exciting!”