I haven't held many big speeches like this, but I know how to pep, says Walz, now Minnesota's governor, to his party colleagues.
So the former football coach launches into a tactical chat about "having the ball and playing offensively" for the remaining 76 days of the election campaign, all to get Kamala Harris elected.
A superpower
From the stage in the giant arena in Chicago, Tim Walz tells his story – about growing up in rural Nebraska, his 24 years in the military, and how he fell in love with teaching. He is open-hearted about his and his wife Gwen's IVF struggle to become parents, as a rebuke to the Republicans who want to ban such care. And he emphasizes the importance of helping and respecting his neighbor – regardless of political color.
Tim Walz's superpower is that he is so normal, said Dean Phillips, a representative from Walz's home state of Minnesota, before the speech.
He represents the entire Midwest, including farmers and people living in rural areas.
The audience cheers when Walz tells how he, after hesitation, ran in an election in a Republican red district and won with the addition "never underestimate a teacher".
As governor, Walz has introduced reforms such as stricter gun laws, paid parental leave, and free school lunches – something he proudly tells about from the podium.
When other states ban books, we ban hunger, he says, addressing the Republicans who, among other things, have seen to it that sex education materials have been removed from schools.
Said wrong about guns?
That Kamala Harris chose Tim Walz as her vice presidential candidate came as something of a surprise a couple of weeks ago. Since then, the party's strategists have praised the 60-year-old's folksiness as well as his background as a geography teacher, congressman, and national guardsman.
However, the latter has caused problems for Walz since an interview he did in 2018 where he said he had carried a gun "in war" went viral.
The Harris campaign quickly announced that it was a false statement, Walz took leave shortly before his unit was sent to Iraq in 2004. But Republican Donald Trump and his vice presidential candidate JD Vance have gone hard after Walz, calling him a liar.
Walz did not touch on the dispute in the speech.
But as vice presidential candidate, he is now expected to become an attack dog against the Republicans. It was he who a few weeks ago came up with the epithet "weird", roughly "crazy", about Trump and Vance.
Dean Phillips believes that Walz can attract voters who have felt that the Democrats do not stand for their values.
Moreover, he is the perfect dad jokester. There is something genuine about it that I appreciate.