"Barack knows the American Dream because he's lived it," the first lady told the Democratic National Convention on Tuesday in an address intended to reassure voters that her husband shares their values - hard work, perseverance and optimism - while also drawing a contrast between him and Mitt Romney.
Mrs. Obama never mentioned the president's Republican challenger, who grew up in a world of privilege and wealth.
But the point was clear as she wove a tapestry of their early years together, when money was tight and times were tough, when they were "so in love, and so in debt." She reminisced about the man who now occupies the Oval Office pulling his favorite coffee table out of the trash and wearing dress shoes that were half a size too small. And she told stories about a president who still takes time to eat dinner with his daughters nearly every night, answering their questions about the news and strategizing about middle-school friendships.
With a mix of personal anecdotes and policy talk, Mrs. Obama's speech was her most political yet.
"Today, after so many struggles and triumphs and moments that have tested my husband in ways I never could have imagined, I have seen firsthand that being president doesn't change who you are - it reveals who you are," she said.
To that end, the first lady painted a portrait of a leader who knows the struggles of everyday Americans, who listens to them as president and who pushes an agenda with their interests in mind.
"That's the man I see in those quiet moments late at night, hunched over his desk, poring over the letters people have sent him," she said. "I see the concern in his eyes ... and I hear the determination in his voice as he tells me, 'You won't believe what these folks are going through, Michelle. . It's not right. We've got to keep working to fix this. We've got so much more to do."
She added: "I see how that's what drives Barack Obama every single day."
With such stories, the first lady sought to counter Republicans trying to paint Obama as something other than a typical American, and implied that it was Romney who couldn't relate to people trying to get by in tough economic times.
To be sure, neither Romney nor Obama fits the bill of the average, working-class American struggling with credit card debt and mortgage payments. Both are millionaires who live a privileged life few Americans will ever experience.
But each candidate is trying to convince Americans that they're best suited to run an economy hampered by sluggish growth and high unemployment. Polls show Romney leading on who voters say would best to manage the economy; but Obama has the advantage on who voters believe understands their economic challenges better.
As she stood in the center of the convention's blue-carpeted stage, Mrs. Obama's words went straight to the core of the contrast Democrats are trying to draw between Obama and Romney. They say the president is pushing policies to boost the middle class, while Romney wants to protect the wealthy and hope their success trickles down.
Once a reluctant political spouse, Mrs. Obama delved more deeply into the details of her husband's policies than she has in her previous speeches. She promoted his health care overhaul, push for tax cuts for middle income earners and the auto bailout. And she took on the economy, her husband's biggest political liability, arguing that he "brought our economy back from the brink of collapse to creating jobs again."
"In the end, for Barack, these issues aren't political. They're personal," she said.
The first lady, wearing a bright pink dress, drew thunderous applause from the crowd and chants of "four more years" that are more often reserved for the president.
At the White House, Obama watched his wife's speech with the couple's two young daughters.
"I'm going to try to not let them see their daddy cry because when Michelle starts talking, I start getting all misty," the president said at rally earlier Tuesday in Norfolk, Va.
Mrs. Obama likely will have one more turn in the convention spotlight later this week. She is expected to introduce her husband Thursday night when he accepts the Democratic nomination before a crowd of up to 74,000 and a television audience of millions across the country.
The Obamas' daughters, Malia and Sasha, are also expected to join them on stage during the convention's closing night, leaving voters with fresh images of the photogenic family.
While at the three-day convention, Mrs. Obama will also focus on shoring up support for her husband among key constituencies. She plans to speak to the party's African-American, Hispanic and women's caucuses and address a gay and lesbian luncheon. Along with the vice president's wife, Jill Biden, the first lady will also participate in an armed services event Thursday and put together care packages for U.S. troops serving overseas.
The first lady took the stage Tuesday as the most popular figure in this year's presidential campaign. She earns higher favorability ratings than her husband, his Republican rival, the other contender for first lady or either candidate for the vice presidency, according to the latest Associated Press-GfK poll.
In the poll, conducted before the Republican convention began, 64 percent of Americans said they had a favorable view of Mrs. Obama. The president came in at 53 percent favorable.