Milwaukee Mayor Chevy Johnson has taken to the stage.

He made headlines in June after former President Donald Trump reportedly called Milwaukee "horrible" in a closed-door meeting weeks before the city hosted the Republican National Convention.

"Donald Trump was talking about things that he thinks are horrible. All of us lived through his presidency. So, right back at you, buddy," Johnson said in response during a news conference at the time.

Asked at the time what he meant by the reported "horrible city" comment, Trump told Fox News he was referring to crime in Milwaukee and the 2020 election.

Cincinnati Mayor Aftab Pureval has taken the stage. He is Cincinnati's first Asian American mayor and, like Harris, has a parent who immigrated to the U.S. from India.

New York Rep. Tom Suozzi, who flipped a Long Island seat this winter, reiterated his message on the campaign trail about the need to solve the nation's migrant issue.

"To be a nation of immigrants is hard sometimes, too. You have to work for it," he said.

The DNC marks a culmination of decades of Democratic efforts to take back patriotism after years of Republicans owning messaging around "freedom" and the American flag.

The word "freedom" is seemingly on the lips of every attendee and speaker -- and the name of Beyoncé's hit song and now-campaign anthem. Audience chants of "USA!" puncture speakers' remarks as they wave signs saying the same. Camo hats bearing the names of Vice President Kamala Harris and Minnesota Gov. Tim Walz pockmark the crowd. And musician Jason Isbell performed the country hit song "Something More Than Free."

Read more here about how Democrats have been running on this message, which has long been a staple in GOP messaging.

-ABC News' Tal Axelrod