"We're all here tonight for one beautiful, simple, reason: We love this country," he said as thousands of delegates hoisted vertical placards reading "Coach Walz" in red, white and blue.
Walz described his upbringing in Nebraska and teaching and coaching football in Minneosta and told the crowd, "Thank you for bringing the joy to this fight."
"While other states were banning books from their schools, we were banishing hunger from ours," he said.
Democratic delegates hoisted vertical placards reading "Coach Walz" during his address. (AP PHOTO)
In a dig at his Republican counterpart, JD Vance, he added, "I had 24 kids in my high school class, and none of them went to Yale."
When Walz talked about the difficulty conceiving his daughter, Hope, she made a heart with her hands and held it over her chest. His son, Gus, wept watching his dad speak and at least once shouted, "That's my dad!"
"I haven't given a lot of speeches like this but I've given a lot of pep talks," Walz said.
He also drew on his time as a football coach.
"It's the fourth quarter. We're down a field goal, but we're on offense and we've got the ball. We're driving down the field, and boy do we have the right team," he said.
"Kamala Harris is tough, Kamala Harris is experienced, and Kamala Harris is ready."
Former US president Bill Clinton joined Democratic stalwarts in supporting the Harris-Walz ticket.
Former US president Bill Clinton criticised Donald Trump for mostly talking about himself. (EPA PHOTO)
He denounced Donald Trump as selfish and praised Kamala Harris as focused on the needs of Americans.
"What does her opponent do with his voice? He mostly talks about himself," Clinton said. "So the next time you hear him, don't count the lies, count the I's."
Media personality Oprah Winfrey joined Clinton and others to press the case that while Trump was for himself, Harris was for America.
"I'm calling on all you independents and all you undecideds," Winfrey said, describing herself as an independent. "Decency and respect are on the ballot in 2024."
Stevie Wonder told the Democratic National Convention the US "must choose courage" at the election. (AP PHOTO)
The pair also received a ringing endorsement on Tuesday from former president Barack Obama and his wife Michelle Obama at the Chicago convention.
Harris is set to give a major speech on Thursday night, marking the grand finale of the four-day event.
Earlier Stevie Wonder implored the DNC, "We must choose courage over complacency" before performing Higher Ground as a troupe of dancers grooved nearby.
Meanwhile, Trump has spoken from behind bulletproof glass at his first outdoor rally since last month's attempted assassination.
Donald Trump speaks behind a glass barrier during a campaign rally in North Carolina. (AP PHOTO)
During an event in North Carolina focused on national security, he blamed President Joe Biden and Harris for the deadly Afghanistan withdrawal and wars in Ukraine and the Middle East, while returning repeatedly in his remarks to the Democratic gathering in Chicago.
The former president, now the Republican nominee, asked the crowd at the North Carolina Aviation Museum & Hall of Fame whether they had seen the speeches given by Obama and former first lady Michelle Obama.
"He was taking shots at your president. And so was Michelle. You know, they always say, 'Sir, please stick to policy. Don't get personal'. And yet they're getting personal all night long, these people," he said, asking: "Do I still have to stick to policy?"
Trump also mocked the DNC and its frequent references to him, calling it a "charade."
Agencies
