For Tim Walz, the Convention Is Like Marrying Into a Very Large Family

Roughly 50,000 people are converging on Chicago for the Democratic National Convention, and very few of them have ever seen Gov. Tim Walz of Minnesota in person.

After rising on a comet-like trajectory to become Vice President Kamala Harris’s running mate, Mr. Walz is finding himself the political equivalent of someone marrying into an extremely large family and meeting all the relatives for the first time.

“It’s a big family, and a lot of that family’s cousins served with him in the U.S. House of Representatives or worked with him with the Democratic Governors Association,” said Representative Betty McCollum of Minnesota, who is a Walz-knower of two decades and has been something of a proselytizer for him. “They kind of know somebody who knows somebody who knows Tim. It’s like you’ve been invited to the wedding and you’re the family member of the vice-presidential candidate.”

Picture an aunt or a distant cousin squealing with delight at their first opportunity to hug and pinch the cheek of their new family member. That is essentially what Mr. Walz is going through after he spent the first days of the convention scurrying from one delegation or caucus meeting to another.

At a Hispanic Caucus meeting on Monday, he dived right into his remarks as if he were an old friend. He did not acknowledge the newness of the relationship. To the L.G.B.T.Q. caucus, Mr. Walz began with a review of his recent visits to gas stations in western Pennsylvania before controversially declaring that the ones in the Midwest were superior.

“Wisconsin folks and Minnesotans know it’s all about Kwik Trip,” he said.

Travis Nelson, a state legislator from Oregon, said he had not known much about Mr. Walz before Ms. Harris began her vice-presidential search