She described not only of trying to maintain a normal family life in the White House, but of President Obama’s commitment to his agenda, and about how he agonizes as he pores over letters from Americans in need.

“He reminds me that we are playing a long game here, and that change is hard, and change is slow, and it never happens all at once,” Michelle Obama said. “But eventually we get there; we always do.”

Although she never mentioned Mitt Romney by name, a racially diverse parade of speakers took the Republican presidential nominee head-on — challenging him on taxes, health care, immigration, women’s rights, and abortion.

“Mitt Romney just doesn’t get it,” said Julian Castro, the mayor of San Antonio, in the keynote address.

Exuberant delegates cheered the speakers — including Massachusetts Governor Deval Patrick — who criticized Romney, as the Democrats seized the opportunity to deliver their first, prime-time counterpunch to last week’s Republican assault on them in Tampa.

Michelle Obama’s prime-time speech at Time Warner Cable Arena served as an emotional counter to a similar address delivered last week in which Ann Romney sought to flesh out her husband’s personality and passions.

Michelle Obama spoke of tough financial times she and Barack faced as a young couple, of parents who struggled and inspired them both to reach high, and of what she said has been her husband’s moral and political consistency.

“In the end, for Barack, these issues aren’t political – they’re personal,” she said. “Because Barack knows what it means when a family struggles.”

Michelle Obama recalled the encouragement she received as a child, and how she and the president had been raised by hard, determined caregivers.

“Like so many American families, our families weren’t asking for much. They didn’t begrudge anyone else’s success or care that others had much more than they did. In fact, they admired it,” she said to loud applause.

“We learned about dignity and decency – that how hard you work matters more than how much you make, that helping others means more than just getting ahead yourself.”

Patrick pointedly took issue with Romney, saying he left Massachusetts as the 47th state in job creation; with roads and bridges crumbling; and with business confidence down.

“Mitt Romney talks a lot about all the things he’s fixed,” Patrick said. “I can tell you that Massachusetts wasn’t one of them. He’s a fine fellow and a great salesman, but as governor he was more interested in having the job than doing it.”

Patrick offered a full-throated defense of Obama’s record, and implored Democrats to toughen up and make a more compelling case for what they believe in.

”It’s time for Democrats to grow a backbone and stand up for what we believe,” he said, drawing the cheering crowd to its feet. “I will not stand by and let him be bullied out of office,” Patrick said of Republican attacks on the president.

Castro, in his keynote address, echoed Patrick’s spirited support for Obama and assailed Romney for his vision for smaller, limited government.

“Texas may be the one place where people actually still have bootstraps, and we expect folks to pull themselves up by them. But we also recognize there are some things we can’t do alone,” Castro said. “We have to come together and invest in opportunity today for prosperity tomorrow.”

In a familiar attack by Democrats, Castro derided Romney as out of touch with ordinary Americans.

“A few months ago he visited a university in Ohio and gave the students there a little entrepreneurial advice,” Castro said.

“ ‘Start a business,’ he said. But how? ‘Borrow money if you have to from your parents,’ he told them. Gee, why didn’t I think of that?”

Romney’s campaign seized on the negative attacks, pointing out that they were far from the unifying politics that President Obama had pledged to seek.

“It was just eight years ago Barack Obama’s keynote address promised ‘a politics of hope’ and a rejection of those ‘who are preparing to divide us,’” said Andrea Saul, a Romney spokeswoman. “But that Barack Obama is nowhere to be found now that Americans aren’t better off, with stagnant unemployment, lower incomes, and a poverty rate on track to hit its highest rate since the 1960s.”