In 1996, she became an associate dean at the University of Chicago, directing efforts to engage students in local community service. Her first daughter, Malia, was born in 1998; Sasha arrived in 2001. A year later, with Barack in the Illinois Legislature, she moved to the University of Chicago Hospitals as executive director of community affairs.
After her husband was elected to the U.S. Senate in 2004, she was promoted to university vice president. She took leave from that job to help his presidential campaign.
Finally, as first lady, she was in a position to actually fulfill her ambition to "change the world."
Her first initiative was "Let's Move!" The objective: solve childhood obesity within a generation. People who have worked with her describe a meticulous planner, a goal-setter who translates big-picture strategy into actions that affect real people, a woman who is comfortable being in charge.
"Let's Move!" is now a sprawling effort that includes corporations, teachers, government, Beyonce, and more. But the centerpiece is Mrs. Obama herself.
So one hot day in May of last year, she arrived with just 15 minutes' notice at Alice Deal Middle School in Washington, D.C.
Beyonce's video had just hit the Internet, and students had spent a few gym classes practicing the choreography. All the students were outside on the playground when Mrs. Obama arrived, wearing black slacks and a bright yellow blouse that showed off those arms.
The beat kicked in, the cameras started rolling and the first lady started dancing.
"I was surprised when she did the dances," recalls health and physical education teacher Michelle Ortiz, who spent some time speaking with Mrs. Obama. "She mentioned that she didn't know the choreography, but that she would give it a shot."
She did what the kids did: the running man, the Dougie, the jump rope thing. She picked up the moves quickly. She spoke to the crowd, then asked if they wanted to dance some more.
"Lots of times kids have an issue because they don't have a connection with an adult," Ortiz says. "Like, you could never possibly understand what it's like to be a kid. Now the first lady is doing a dance that we like to do. It shows like, wow, she's still in touch."
Quite literally: "She gave me a hug," Ortiz says. "She smelled really good, like nice perfume. I didn't realize how tall she was."
Assistant principal Diedre Neal got one, too, and said it didn't feel obligatory: "It's like hugging a family member. It's not something you can fake. . It's more comforting, I wouldn't say strong. Solid and comforting. Motherly."
The first lady's bubble is a powerful thing, erected and enforced by a team of 23 staffers (about the same number as Mrs. Bush had). Unplanned encounters are rare. Coming face to face with conservatives is rarer still — but they still make themselves heard.
In the fall of 2011, she was on a trip to promote Joining Forces, another initiative that, among other things, has helped 50,000 veterans and military spouses get jobs, with commitments from 1,600 companies to hire at least 160,000 more. While being introduced with the vice president's wife, Jill Biden, at a NASCAR race in Homestead, Fla., boos could be heard from the crowd.
Never mind that she was standing with an Army sergeant who had served in Iraq and Afghanistan, his wife and their three children. Clearly, there was something about her persona the crowd did not like.
The next day, Rush Limbaugh described it:
"We don't like being told what to eat; we don't like being told how much to exercise; we don't like being told what we've got to drive; we don't like wasting money; we don't like our economy being bankrupted. We don't like 14 percent unemployment," the radio titan said, segueing from Mrs. Obama's programs to conservative views of her husband's policies.
"I'll tell you something else," he told his audience, estimated at 15 million people per week. "We don't like paying millions of dollars for Mrs. Obama's vacations."