Facing disappointing poll numbers that nearly knocked him off the main GOP debate stage twice, Mr. Christie is seeking to reboot his campaign by promoting himself as an outsider who still has governing experience, showing a willingness to compete in Iowa and grinding out more than two dozen voter meetings in New Hampshire.

“These races, unfortunately for folks like me, are about patience,” Mr. Christie said in an interview ahead of his 21st New Hampshire swing concluding Friday. “When you are tested and you come through, it just makes you better, stronger and more patient. All those things have helped make me a better candidate and ultimately will help me win this race.”

The rise of celebrity businessman Donald Trump in the polls supplanted Mr. Christie as the tell-it-like-it-is candidate in many voters’ minds, and left him looking measured to parts of an electorate yearning for someone bold.

“He’s a more dignified version of Trump’s outspokenness,” said James Kaklamanos, a Nashua resident who likes Mr. Trump but came to see Mr. Christie at a Manchester diner Thursday morning.