"I think we owe it to the American people to tell them exactly what she'd do as president before we ask them for their votes," he said. "So here’s the part you clip and save and send to that undecided relatives."

Walz continued, "If you’re a middle-class family or a family trying to get into the middle class, Kamala Harris is gonna cut your taxes. If you’re getting squeezed by the price of your prescription drugs, Kamala Harris is gonna take on Big Pharma. If you’re hoping to buy a home, Kamala Harris is gonna help make it more affordable. And no matter who you are, Kamala Harris is gonna stand up and fight for your freedom to live the life you want to lead."

After focusing on his own biography, Walz turned to skewering Trump and Vance -- and brought back the phrase that made him go viral during the veepstakes: "weird."

"Here's the thing. It’s an agenda that nobody asked for," he said of the Trump-Vance platform. "It’s an agenda that serves nobody but the richest people and the most extreme voices in our country. An agenda that does nothing for our neighbors in need."

"Is it weird? Absolutely," he said. "But it's also wrong."

As governor, with the help of a narrow Democratic majority in the state legislature, Walz implemented a bevy of progressive policies including: universal school breakfast and lunch, state codification of abortion rights and gun control measures like universal background checks and red flag laws.

He discussed his personal connection to each issue in tonight's speech, including his family's IVF journey and being a hunter supportive of the Second Amendment but also a father who worries about guns in schools.

"That’s what this is all about," he said. "The responsibility we have to our kids, to each other, and to the future we’re building together -- a future in which everyone is free to build the kind of life they want. But not everyone feels the same sense of responsibility."

In his speech, Walz touted how he won his first election for Congress in a "deep red district."

While it's true that the district had an entrenched Republican incumbent and he wasn't given much of a chance at first, the district was actually pretty competitive under the surface. In the 2004 presidential election, George W. Bush carried it just 51% to 47%.

—538's Nathaniel Rakich