Barack and Michelle Obama electrify Democrats but warn of tight race

But Mrs Obama, whose most memorable line from her last convention speech in 2016 was, “when they go low, we go high”, did little to lower the temperature of the heated political rhetoric that has divided the country over the last decade.

She attacked Donald Trump for assailing her family and continuing to push “ugly, misogynistic, racist lies as a substitute for real ideas and solutions that will actually make people’s lives better”.

In a broadside that generated some of the loudest cheers of the night, she mocked Trump for his use of the term “black jobs” on the campaign trail.

“Who’s going to tell him that the job he’s currently seeking might just be one of those Black jobs?” she said, referring to her husband’s presidency.

Earlier in the night, Second Gentleman Doug Emhoff, Ms Harris’s husband, shared personal stories about the vice-president, including how they were set up on a blind date by one of his clients in 2013.

He spoke about their “big, beautiful, blended family”, referring to his son, Cole, and daughter, Ella, from his first marriage. He described Ms Harris as a “joyful warrior” and a supportive parent who put their family first despite the demands of her job.

Ms Harris, who was flying back from a campaign rally in Milwaukee during her husband’s speech, kept Air Force Two in the air so she could watch his speech live, according to the White House.

Mr Emhoff said the two would celebrate their 10th anniversary on Thursday night, when Ms Harris formally accepts the party’s nomination in a primetime speech.

“Kamala was exactly the right person for me at an important moment in my life,” he said. “And at this moment in our nation’s history, she is exactly the right president.”