“So there I was, a 40-something high school teacher with young kids, zero political experience, no money, and running in a deep-red district,” he said as he recalled his foray into the US Congress. “But you know what? Never underestimate a public school teacher.”

Walz’s appearance in Chicago comes one day before Harris herself makes history and becomes the first black and south Asian woman to accept her party’s nomination to run for president.

After a rollicking roll-call and blistering speeches by the Obamas the night before, day three of the convention featured luminaries such as former president Bill Clinton. He framed the election as a clear choice between Harris, who was “for the people” and Trump who “is about me, myself and I”.

Former speaker Nancy Pelosi – the person Democrats should credit most for pressuring President Joe Biden to quit the race for a second term – took the stage too, highlighting Trump’s role in the January 6 attack and the threat he posed to democracy, without ever mentioning his name.

And the party’s future generation of leaders was also on display, with rising stars such as Transport Secretary Pete Buttigieg, Maryland Governor Wes Moore and Pennsylvania Governor Josh Shapiro using their speeches to drive home the key theme on the night - freedom - and take aim at the man they say is trying to take freedom away.

“Donald Trump is like the old boyfriend who you broke up with, but he just won’t go away,” said the hip hop-loving, sneakers-wearing House Democrats leader Hakeem Jeffries.

“He has spent the last four years spinning around the block, trying to get back into a relationship with American people. Bro, we broke up with you for a reason!”

But it was Oprah Winfrey who stole the show, making a surprise appearance in her former city to appear at a political convention for the first time and implore independent and undecided voters to “choose common sense over nonsense”.

“Soon, and very soon, we’re going to be teaching our daughters and sons about how this child of an Indian mother and a Jamaican father, two idealistic, energetic immigrants … grew up to become the 47th president of the United States,” said Winfrey, who identifies as an independent voter.

“Values and character matter most of all, in leadership and in life. And more than anything, you know this is true, decency and respect are on the ballot in 2024.”

Decency was on full display as Walz entered the stage, often placing his hand on his heart and bowing in gratitude to the crowd as they held up signs saying: “Coach Walz”.

But the affable governor has also faced scrutiny recently, including questions about embellishing his background.

For instance, his wife this week clarified that she did not undergo IVF, as Walz has repeatedly claimed, but that she used other fertility treatments.

Republicans also have slammed him for a 2018 comment he made about having carried weapons in war. (He served in the National Guard for 24 years, but his only wartime deployment was to Italy in 2003, backfilling troops that were deploying to Afghanistan).

And when he first ran for Congress in 2006, his campaign repeatedly made false statements about the details of a 1995 arrest for drunk and reckless driving.

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Democrats, however, stand by their Midwest “dad in plaid”, convinced that his presidential pairing with city slicker Kamala Harris showcases the diversity of America, their positive vision for the future and the big tent of the Democratic Party.

Soon, they’ll know if most voters agree.

“Look, we’ve got 76 days. That’s nothing. There’ll be time to sleep when you’re dead,” Walz said in closing his speech. “We’re going to leave it on the field. That’s how we’ll keep moving forward. That’s how we’ll turn the page on Donald Trump.”

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