As it turned out, traditionally conservative-leaning senior citizens would help propel Mr. Biden to the presidency, and he had stronger appeal in the primary campaign among Black voters than any of his rivals did.
Now on the verge of entering the White House, Mr. Biden has signaled his intent to gather his faithful squad together again with the alacrity of a coach rallying his team for one last game. This past week, he named Mr. Vilsack as his choice for agriculture secretary. He has picked Mr. Kerry for a top climate post. And Antony J. Blinken, a longtime top aide to Mr. Biden who was spotted in Iowa with him, is now his choice for secretary of state.
If Mr. Biden’s selections so far underscore his experience and his deep bench of long-lasting relationships, it is also a stark reminder of his roots in an older, whiter generation that has at times seemed at odds with the energy in the current Democratic Party.
He may not have won over youthful crowds a year ago, but he is, his team insists, committed to empowering the next generation of Democratic leaders.
At a briefing with the news media on Friday, the incoming White House press secretary, Jennifer Psaki, made a point of highlighting younger members of Mr. Biden’s team. Mr. Biden has also named a number of people of color to major cabinet positions, including helming the Pentagon and the Homeland Security Department, even as he faces intense pressure from some in his own party who believe he needs more people of color in senior positions.
Not everyone who assisted him, even in Iowa, is so far an administration choice, including Mayor Keisha Lance Bottoms of Atlanta, who joined Mr. Kerry on the bus tour.
Mr. Kerrey also said he was not on Mr. Biden’s list.
“There are a lot of people that have endorsed Joe Biden that aren’t going to be in his cabinet,” he said. “You’re talking to one.”
Thomas Kaplan contributed reporting.