Doug Emhoff, the second gentleman, drew on his decade-old relationship with Vice President Kamala Harris in a passionate pitch for her candidacy on Tuesday night at the Democratic National Convention, urging Americans to follow his lead in trusting her with their families’ futures.

Mr. Emhoff spoke directly to his wife during his address, expressing his admiration for how she has navigated one of the most tumultuous times in modern presidential politics. Soon after Mr. Biden dropped out of the race, Ms. Harris took the helm of the party, infusing enthusiasm and quickly reversing its fortunes.

“That’s who she is,” Mr. Emhoff said. “Whenever she’s needed, however she’s needed, Kamala rises to the occasion.”

Like other convention speakers who have been charged with reintroducing Ms. Harris to the American public, Mr. Emhoff pointed to her personal attributes and humanity. He said he had fallen in love with Ms. Harris the more he learned what drove her.

“It is what you have seen over these past four years and especially these past four weeks,” he said. “She finds joy in pursuing justice. She stands up to bullies just like my parents taught me to. She likes to see people do well, but hates when they are treated unfairly. She believes this work requires a curiosity in how people are doing. Her empathy is her strength.”

He also engaged in some self-deprecation, telling a story about how, fresh off a divorce and trying to navigate life with two children, he was presented with Ms. Harris’s phone number and the prospect of a blind date.