"I think in the grand scheme of things, it won't make any difference. I think the convention will appear to be greatly united," McConnell told CNN.
Cruz's 20-minute long speech Wednesday night flipped the already chaotic GOP convention on its head, as Republicans booed him off the stage and his wife had to be escorted from the arena by security.
Cruz poured fuel on the fire Thursday, telling Texas delegates he was not ready to endorse Trump
because of Trump's attacks on his family.
McConnell declined to say whether Cruz should endorse Trump to help unite the party.
"That's really up to him. I think it would be helpful if he did. But, you know, there are plenty of people who have signed up," McConnell told CNN. "I think the broad Republican Party, the right-of-center world, is going to be largely united."
McConnell and Cruz have been antagonists ever since the tea party senator accused McConnell, the Senate's top Republican, of lying
. McConnell, who is fighting to maintain control of the Senate in the November, also urged Trump not to go off-script Thursday night when he addresses the Republican convention.
"I think that there are basically a couple of things he needs to do. Number one, I'm a strong advocate for having a great script and sticking to it," McConnell said. "And that's the way you avoid making mistakes and driving home the message that America needs to change."
McConnell said that Republicans need to be united against Clinton, but he disagreed with Republican delegates who have been chanting "Lock her up."
Asked if she should go to jail, McConnell said, "No. But I think clearly the FBI director pointed out, in great detail, all the ways in which she has not leveled with the public over the last couple of years. It couldn't have been more clear by one of the most credible people in the country."
McConnell also said he "totally" disagreed with Trump's comments to The New York Times saying that the U.S. wouldn't defend NATO allies
if they haven't "fulfilled their obligation to us."
"Yeah, I disagree totally with what he said about NATO," McConnell said. "It's the most important military alliance in world history. It remains relevant today. Many Americans don't know the operation in Afghanistan has been a NATO operation. And I want to reassure our NATO allies that we will come to the defense of any member that is threatened."