"There's nobody tougher, there's nobody smarter," Trump said of McConnell to a cheering crowd of some 6,000 supporters in the senator's home state. "He stared down the angry left-wing mob."
McConnell briefly took the stage and praised Trump for his judicial nominations, asking him to keep it up.
Trump said that Democrats "demonized" Kavanaugh before knowing anything about him.
"What happened to him was so unfair, I've never seen anything like it," Trump said. "And we stuck with him all the way because we knew the facts."
Trump went on to compliment McConnell further.
"He goes down as the greatest leader, in my opinion, in history," the president said.
"He’s better when I’m president than he ever was when anybody else was president," he added, smiling.
Trump's praise Saturday contrasts with his criticism of McConnell in the past, especially during the Republican effort to reform healthcare last year, when he once told reporters he was "very disappointed" in McConnell.
Kind words were similarly shared between Trump and Kentucky Sen. Rand Paul, who himself has not always been on the best of terms with the president.
“Some of you may remember that once upon a time he was not my first choice for president -- but I will tell you, he grows on you,” Paul said to the crowd before Trump arrived. "I will also tell you that every day, virtually every day, he exceeds my expectations."
For his part, Trump praised Paul as "a senator of great common sense."
While taking credit for many economic achievements since taking office, Trump stopped to focus on coal, which represents a large market in Kentucky.
"We have ended the war on clean, beautiful coal," he said. "We're putting our miners back to work like never before."
Trump came to Kentucky to support Republican Congressman Andy Barr, representing Kentucky’s 6th Congressional District, where the rally took place. The president called Barr "a great congressman," and implored the audience to vote for him.
Barr is facing off against Democratic challenger Amy McGrath, a former Marine fighter pilot, on Nov. 6.
Though Trump praised military members during his talk, he did not reference the combat experience of McGrath, whom he described as "an extreme liberal."
Trump also attacked Democrats more broadly.
"The Democrats have become totally consumed by their chilling lust for power," he said.
Later on, Trump described the Democratic party as the "party of crime," billing the GOP as the "party of safety."
Before leaving the White House for the Richmond rally, Trump met with Pastor Andrew Brunson, who was just released after almost two years of detention in Turkey. He commented on the matter during the rally.
"That one wasn't easy," Trump said. "And we don't pay ransom. We don't pay ransom."
Some attendees in Richmond told ABC News they cared most about specific issues, such as coal jobs in Kentucky, or repealing Roe v. Wade, while others called themselves moderates and came merely to witness their president speak.
Three more rallies in key midterm states -- Montana, Arizona and Nevada -- were announced for next week as Trump was still on stage in Kentucky.