As Democrats in Washington and beyond absorb the chaotic dawn of a new Trump administration, one of the party’s ambitious, young leaders is cautioning them to remain calm.

Speaking on Thursday to a group of young, Democratic elected officials, Transportation Secretary Pete Buttigieg made a case for reorienting how the party communicates with voters, even as he warned that expressing outrage at President-elect Donald J. Trump would not be enough to lead Democrats to victory.

Mr. Buttigieg’s speech — part of a conference about how to “advance center-left policies despite the challenging national political landscape” — was the latest in a set of public remarks from prominent Democrats jockeying to try to lead the party back to power. But unlike Govs. Gavin Newsom of California and JB Pritzker of Illinois, Mr. Buttigieg will soon be unemployed and without the bully pulpit of a state to vocally fight back against Mr. Trump’s policies.

Instead, he suggested, he would spend time defending President Biden’s legacy by reminding the public of the administration’s accomplishments, which he said he expected Mr. Trump to try to claim credit for.

Mr. Buttigieg’s most direct admonition to the gathered Democrats, at a Washington hotel, was for them to not allow themselves to be so outraged by the Trump administration that they would neglect working for their constituents.

“We cannot be mesmerized by the worst things that we see happening,” Mr. Buttigieg said. “We will be inclined to react with shock by some things that are done precisely with the intent of shocking us, we need to move very quickly through the shock.”