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

As he reflected on running for Congress in red district as a Democrat, Walz told the crowd: "Never underestimate a public school teacher."

The line got a loud cheer from the audience.

3:08

Walz says 'never underestimate' a teacher during DNC speech

As he reflected on running for Congress in red district as a Democrat, Walz told the crowd: "Never underestimate a public school teacher."

Walz served in the Army National Guard for 24 years but his characterization of his service over the years has garnered some controversy -- and is the subject of criticism from his vice presidential rival JD Vance.

"I joined up two days after my 17th birthday and I proudly wore our country’s uniform for 24 years," Walz said.

Read more about Walz and Vance's military records here.