Asked on ABC's "This Week" whether he would use the word "irredeemable" to describe many of Trump's supporters, the Virginia senator and Clinton running mate said he wouldn't.
"That's not a word I would use. I wouldn't use it," Kaine said.
Clinton had told a roomful of donors: "To just be grossly generalistic, you can put half of Trump supporters into what I call "the basket of deplorables." Right? Racist, sexist, homophobic, xenophobic, Islamaphobic, you name it."
Clinton has since said she shouldn't have used the word "half" -- but has stuck with her criticism of many of Trump's supporters, including white nationalist David Duke.
But Kaine said some of Trump's supporters will never be persuaded to back Clinton.
"I think we would be unrealistic to think that some people are going to fundamentally change their view. If they've held to a view for five years, as Donald Trump has, that President Obama is not a citizen of this country, I don't think they're going to change their views," Kaine said.
However, Kaine said, others can be won over -- pointing to progress in his home state of Virginia, which when he was born still had segregated schools and wouldn't let women into the University of Virginia.
"Today we've opened the doors of opportunity and our economy is in the top 10 and people who fought in every step of the way have realized, 'Wait a minute, we're better when we let everybody around the table, we're actually a stronger,' " Kaine said.
"I've seen that transition work in my state from fighting against equality, fighting against inclusion to embracing it and being stronger as a result," Kaine said, echoing Clinton's "stronger together" campaign-trail theme.
"That's what stronger together means -- I've seen it work in Virginia and I know that that's the path we're on as a nation," Kaine said. "That's the choice."