The first reason, she said, was that Washington was now the Obamas’ home and they had always been taught to listen and not just pass on by. The second reason identified the audience and framed the approach that would define this most uncommon first lady’s agenda for the next eight years.

“I think it’s real important for young kids, particularly kids who come from communities without resources, to see me, not the first lady,” she said. “To see that there is no magic to me sitting here. There are no miracles that happen. There is no magic dust.”

With the 13 teenagers seated in a semicircle, Obama shared the setbacks and self-doubt she faced as the daughter of black working-class parents in Chicago. When people told her she couldn’t achieve something, she set out to prove them wrong. One step at a time, she climbed, and now she felt an obligation to share.

“When you get, you give back,” she said.

Obama would give much bigger speeches on much bigger stages as she became one of the most famous people in the world. For many Democrats, she was the moral voice of the 2016 presidential campaign, calling out Republican Donald Trump for trafficking in “prejudice, fears and lies.” For other fans, she was simply the first lady who went viral, making them smile with her eclectic fashion choices and her energetic, sometimes goofy pitches for healthier eating.

The heart of Obama’s efforts, however, was a message about the persistent inequities of race, class and gender in America. In scores of speeches and projects, she turned again and again to the stacked deck. These were the themes and conundrums that animated her work before she reached the White House and now seem certain to shape her choices after she departs.

For all the grief she took from critics who conjured radicalism, grievance or, bizarrely, racism from her finely tuned remarks, Obama’s antidotes were fundamentally timeless and conservative. More than anything, she used the strength of her own Chicago-to-Princeton-to-the-White-House narrative to urge kids to believe in themselves and never quit. She mastered the levers of popular culture and harnessed the convening power of her office and her carefully curated brand to establish partnerships with the private sector.

Children hug Michelle Obama as she visits Mary’s Center, a D.C. nonprofit organization that helps people with limited access to health services, in 2009. (Nicholas Kamm/Agence France-Presse via Getty Images)

Obama addressed obesity, which disproportionately affects low-income families and children of color. She worked to increase arts education in poorly performing schools and ease the path for aspiring first-generation college students. She dispensed hugs to thousands of children, saying in a simple embrace that she believed in them. At a BET special, she called out, “Black girls rock!”

A straight-talker by temperament, she modulated her tone in deference to the role. Eternally disciplined and pragmatic, she never swung for the fences. Critics on the left chided her for not being bold enough, as she acknowledged last year. Her answer: “These were my choices, my issues, and I decided to tackle them in the way that felt most authentic to me — in a way that was both substantive and strategic, but also fun and, hopefully, inspiring.”

When Obama took up her unpaid job three days after her 45th birthday, she faced vast and conflicting expectations. She was the first African American first lady in a country that was anything but post-racial. She was the magnetic campaigner who told audiences that power concedes nothing without a struggle. She was the highly educated, professionally accomplished mother of two young daughters who smilingly adopted the moniker of “mom in chief.”

“From the moment we walked in the door, people have wanted to get inside her head and figure her out. ‘Is she in this box or that box? Why isn’t she doing this or doing that?’ ” said Jocelyn Frye, a Harvard Law School friend who became Obama’s first policy adviser. “She’s not a person who lives in boxes. It’s just not that simple.”

The personal story that Obama carried into the White House in January 2009 was enough to etch her name in the history books even if she did not accomplish anything more. She called herself “the little black girl from the South Side of Chicago.” As she would say later, her ancestors had arrived in the United States in chains and now she and Barack Obama were living in a home that slaves helped build.

But in other ways, too, Obama brought a set of experiences markedly different from her modern-day predecessors. Of the previous eight presidents, four had been governors, four had been vice presidents. Their wives had lived in the public eye. Obama was a young Chicago professional, a working mother in a big city who spoke openly about juggling jobs, chores and child-rearing with her increasingly famous and preoccupied husband.

By upbringing, she was urban and attuned to issues of prejudice, hardship and inequality. She adored her father, Fraser C. Robinson III, a gregarious aspiring artist who spent his working life as a shift worker in the city water plant. A swimmer, boxer and soldier as a young man, he was diagnosed with multiple sclerosis in his 30s. His health deteriorated, and he went from one crutch to two to a motorized cart. He died in 1991 at age 55, still working at the plant.

Both of Obama’s grandfathers had come north in the Great Migration, and many members of the Robinson and Shields families lived nearby. Purnell Shields, a talented carpenter and Obama’s maternal grandfather, was barred as an African American from the labor unions that claimed the highest-paying jobs. Fraser C. Robinson Jr. spent much of his career as a postal worker. If he had been born white, Obama once said, he would have been a banker.

Obama spent time with this extended family. She knew them all, from those who were prospering to those who were ailing or just getting by. She also knew countless schoolmates who seemed hardly different from her, yet had fallen short of their ambitions. When Barack Obama met her in 1989, he detected a sense of vulnerability that he traced to Michelle’s sense that life was “terrifyingly random.” She called herself “a statistical anomaly.”

After ditching the prosperous law firm, where she found the work soulless and many colleagues narrow, she spent two years doing economic development work at City Hall with future White House adviser Valerie Jarrett. Next, in what she described as the happiest phase of her working life, she built the Chicago office of Public Allies, a nonprofit leadership training program with roots in community organizing.

Next, she spent a dozen years as an administrator at the University of Chicago, where she elevated the interests of neighboring African American communities. Much as she would in the White House, she searched for ways to connect a powerful and often remote institution with communities where it could do some good. Comfortable and connected in both worlds, she saw herself as a bridge.

In 2001, protesters seeking more construction jobs for African Americans at the university medical center said she should be fired. One said Obama and her colleagues were looking out for themselves and did “not have the best interests of blacks at heart.” Obama persisted. In the next seven years, 42.9 percent of the hospital’s spending on new construction, or $48.8 million, went to firms run by minorities or women, according to university figures.

The focus was not new. At Harvard Law School, where the tenured faculty was 96 percent white and 92 percent male, Obama spoke up for greater diversity. Charles Ogletree, a mentor and professor, pinpointed her passions early.

“Everything she wrote, the things that she was involved in, the things that she thought about,” he recalled of her law school years in the mid-1980s, “were in effect reflections on race and gender. And how she had to keep the doors open for women and men going forward.”

Michelle Obama exercises with children from Orr Elementary School in Washington, D.C., on Sept. 6, 2013. (Marvin Joseph/The Washington Post)

One of Obama’s signatures was the push for a seat at the table — or in “the room where it happens,” to borrow from “Hamilton,” the Broadway musical the Obamas admire. A few years ago, she told a gathering of White House interns that if they were not prepared to risk their power when they claimed that seat, they needed to make room for someone who would.

In reaching the most rarefied of tables, she figured she had four years, maybe eight, to make something happen, to “move the needle,” as she put it. As the media made a fuss over a new hairstyle, she once explained how she saw the role of first lady: “We take our bangs and we stand in front of important things that the world needs to see. And, eventually, people stop looking at the bangs and they start looking at what we’re standing in front of.”

Obama saw early that she could connect with disadvantaged young people by describing her South Side upbringing and the choices she made in her life. Even as the Obamas set out unambiguously to be the president and first lady for the entire country, they were determined “to look out for people who historically have not had people looking out for them,” Valerie Jarrett said in an interview. “Certainly, African American women and girls see themselves in her in a unique way.”

The White House portfolio included Let’s Move, her childhood obesity project, and efforts to open the White House and its grounds to kids who barely knew where it was and never imagined stepping inside. She established Joining Forces to help the military and their families with jobs and workplace issues and started a small mentoring program that became a personal cause.

She worked on homelessness among veterans and pushed Reach Higher, seeking to increase post-secondary education for low-income adolescents. Finally, she launched Let Girls Learn, an international initiative designed to improve access to secondary school for millions of girls around the world who found themselves on the outside looking in.

Throughout, Obama made clear to her staff that she favored coherent projects backed by creative but realistic thinking. She sought buy-in from federal agencies, state governments and private partners, and she wanted to make use of every opportunity. She told her aides, “Don’t just put me on a plane, send me someplace and have me smile.”

“She never looked at things esoterically or theoretically. It was practical and real,” said Democratic strategist Stephanie Cutter, who advised her at key moments. “Her focus was never ‘How do I move Washington?’ It was much bigger than that. It was ‘How do you mobilize a country? How are real people outside of Washington going to see things?’ ”

At the White House, she staged arts events, from dance, music and spoken word to food and design workshops. She made sure that artists who were performing for well-heeled East Room audiences at night were teaching children at the White House or local schools during the day. Her tastes tilted to designers, artists, playwrights and directors of color, choices that alerted millions of Obama-watchers to work they might not have seen or heard.

In 2011, she helped launch Turnaround Arts, a program designed to deliver arts teaching, inspiration and supplies to some of the worst-performing schools in the country — often in places where arts programming was a budget casualty. From eight pilot programs in 2011, the project now reaches 68 schools, with 20 to be added in 2017.

“She knows the power of the arts. It’s visceral and it’s who she is,” said Megan Beyer, executive director of the President’s Committee on the Arts and Humanities. “Every time we do an event, she’ll look at the audience and she’ll say, ‘This is not a fluke. This is what happens when you invest in these kids.’ ”

To critics on the right, including former Alaska governor Sarah Palin, who mocked or denounced new science-based standards for school lunches as overly intrusive, Obama urged them to look more closely. She pointed to the millions of low-income children who depend on those meals and the federal government’s help in paying for them.

“We simply can’t afford to say, ‘Oh, well, it’s too hard, so let’s not do it,’ ” Obama said in 2014. When lobbyists persuaded Congress to count one-eighth of a cup of tomato paste in pizza sauce as the equivalent of a half-cup of vegetables, she wrote dismissively in the New York Times, “You don’t have to be a nutritionist to know that this doesn’t make much sense.”

President Obama and the first lady, along with their guests, wear 3-D glasses at a Super Bowl party at the White House in 2009. (Pete Souza/The White House)

Inside the East Wing, Obama commanded intense loyalty from her staff and set her own agenda, down to the number of public days on her schedule — two at first, while Malia and Sasha were getting settled, and later three. She stayed closer to home than Laura Bush and Hillary Clinton, who each traveled abroad more than twice as much, and put limits on her campaign trips, especially when not campaigning for her husband.

She tightly controlled her message. In eight years, she never gave a news conference, although she held a select few roundtables with reporters. She rarely granted interviews to the beat reporters who knew her work the best. More often, and more strategically, she granted face time to grateful personalities and comedians, along with media outlets carefully chosen for the audiences they reached.

Aides and friends were barely more accessible. When reporters called, former chief of staff Jackie Norris once said, Obama expected her friends to “check in and have conversations and make sure that it’s good for her.” Mostly, the friends did.

The first family prepares to board Air Force One on Aug. 21, 2016, after their vacation on Martha’s Vineyard, in Massachusetts. (Steven Senne/Associated Press)

Since the beginning of the first presidential campaign nearly 10 years ago, Obama has credited her girlfriends with keeping her grounded amid the maelstrom. “When you’re isolated, that’s when you need your girls. They can keep you together when no one else can,” said Angela Kennedy, a D.C. public defender and former Princeton roommate who sees Obama regularly. “She’s smart. She recognized that.”

Not trailed by the presidential press pool, Obama escaped to the gym, restaurants, theaters and her friends’ houses, as well as the occasional trip to the presidential retreat at Camp David. It helped to have her mother, Marian Robinson, now 79, living on the third floor of the White House. “I can always go up to her room and cry, complain, argue,” Obama said. “And she just says, go on down there and do what you’re supposed to do.”

Obama spoke often of what it meant to have normal family dinners and activities with Malia and Sasha, talking about the girls’ doings and keeping things light. She has always been able “to stay above the fray,” said Frye, her Harvard friend, in part by “meeting with real people and talking about real-world problems. At the end of the day, she has kept her head.”

Obama’s ascendance — as mother, mentor, leader and critic — carries many meanings in American culture, particularly as an African American woman, said Nell Irvin Painter, an emeritus professor of American history at Princeton.

“Her power is a symbolic power,” Painter said, noting the way Obama “has conducted herself as first lady. She has grace, there is no question, but I would add elegance. It’s a kind of assurance that is also something new for a black woman in public life. She is the symbol of what an American can be. Michelle Obama has presented a universal American identity.”

Michelle Obama blows kisses to graduates after delivering the commencement address for Bowie State University, a historically black university, in Maryland in May 2013. (Chip Somodevilla/Getty Images)

On May 9, 2015, Obama took the stage at Tuskegee University in Alabama and delivered the most thorough and personal speech about race and racism of her tenure. As a speechmaker, said author Garry Wills, who won a Pulitzer Prize for his study of Lincoln’s Gettysburg Address, “I don’t know that she has any competitors in women’s history.” She wowed millions of fans with keynote addresses at three successive Democratic National Conventions, but she also had a serious body of work that received less attention in mainstream circles.

Many times before her Tuskegee appearance, she had spoken about the country’s history of violence and discrimination against African Americans. She did it in Orangeburg, S.C., in 2007 to woo black support for her husband’s candidacy. She did it in Nashville during the 2012 reelection campaign, and in Topeka, Kan., in 2014 to mark the 60th anniversary of Brown v. Board of Education. And she did it at other historically black universities, including Bowie State, Jackson State and North Carolina A&T.

Together, the talks reflected a lifetime of thinking about the shifting landscape of racism, the advances and the setbacks. At Tuskegee, she spoke of slights and hurdles while suggesting strategies — tested by her own experience, as always — to block out the noise and navigate a path forward.

“Here’s the thing: The road ahead is not going to be easy,” she told the graduates in an address that tracked the history of the Tuskegee Airmen, a storied black flying squadron in World War II. “It never is, especially for folks like you and me. Because while we’ve come so far, the truth is that those age-old problems are stubborn and they haven’t fully gone away. So there will be times, just like for those Airmen, when you feel like folks look right past you or they see just a fraction of who you are.”

“Too many folks feel frustrated and invisible,” Obama said. She cited worries about being pulled over “for absolutely no reason,” or being overlooked for a job “because of the way your name sounds,” or sending children to schools “that may no longer be separate, but are far from equal.” Above all, she said, there is the “realization that no matter how far you rise in life, how hard you work to be a good person, a good parent, a good citizen, for some folks, it will never be enough.”

The Obamas were not immune, despite their efforts, their achievements, their conduct. For years, Donald Trump sowed doubts about Barack Obama’s birth and citizenship, while talk show host Rush Limbaugh told his millions of followers that Michelle suffered from “uppity-ism” and called her “Michelle My Butt.” Foes likened her to a character from Planet of the Apes, a Star Wars Wookiee and a gorilla, a racist slur with a particularly long and ugly history. They challenged her patriotism and even questioned her gender.

But no matter how grim the outlook and how significant the structural challenges, Obama said at Tuskegee, despair and anger are “not an excuse to just throw up our hands and give up.” Instead, she proposed the measured, practical, traditional responses that had worked for her. Study, organize, band together, be a mentor, help a cousin fill out a financial aid form and “vote, vote, vote.”

“You have got everything you need to do this. You’ve got it in you,” she said in her best I-believe-in-you tone. “Most of all, you’ve got yourselves and all of the heart, grit and smarts that got you to this day.”

It was never Obama’s style to summon people to the barricades. She drew criticism from some African American intellectuals and activists for perpetuating a bootstraps narrative that said black people must be twice as good to do just as well as whites. Painter recognized the critique but saw Obama’s message differently.

“She also says you can figure it out. That’s a crucial part,” Painter said. “Her commentary to black kids is, ‘You can do it. It’s not just lecturing and shaking her finger in their faces, but an encouragement. It’s pragmatic, but the way she phrases it, it is full of empathy and I think there is still a lack of empathy in the way the United States speaks to black people.”

The response to Obama’s remarks provided proof aplenty. Conservative talk show host Laura Ingraham saw “a litany of victimization.” Media comment boards filled with talk of a “tirade” and an “America-hater” and an “angry woman who has no appreciation for the many gifts our country has bestowed on her.” Someone wrote, “Can she or her husband ever just be Americans? Why do they always have to focus on their skin color? Repulsive.”

But also, “Michelle for President!” — something that Obama, whose favorability ratings routinely topped 60 percent, has said will never happen. “No. Nope. Not going to do it,” she said earlier this year.

Michelle Obama campaigns with Hillary Clinton in Winston-Salem, N.C., on Oct. 27, 2016. (Melina Mara/The Washington Post)

Michelle Obama was dismayed by the rise of Donald Trump. She perceived danger in the candidacy of an unstudied Republican who lied with abandon and routinely mocked and disparaged rivals, critics and entire swathes of the American populace, all the while vowing to wreck much of what the Obama administration spent eight years building.

“This is not normal. This is not politics as usual,” Obama declared at an October rally in New Hampshire after a tape surfaced of Trump boasting about grabbing women by the genitals. A growing number of women said they had been accosted. “I know it’s a campaign, but this isn’t about politics. It’s about human decency. It’s about right and wrong.”

Obama said repeatedly during the campaign that Trump was dangerous, undeserving and lacking “any idea what this job takes.” In Philadelphia, she pointedly recalled Trump’s leadership of the birther movement, referring to the “hurtful, deceitful questions deliberately designed to undermine” her husband’s presidency.

The attacks on Trump were the strongest, sharpest words Obama uttered in public during the White House years. Whatever her anger or dismay, she never said she was surprised, for these were the regressive forces that she had seen in action her entire life.

On a weekday morning, with not many people watching, Obama delivered her take on the political moment. To a rapt church audience — men and women, white and black — she said in a tone more suited to a seminar than a rally, “My fear is that we don’t know what truth looks like anymore.” She spoke of her hard-won understanding of the world, drawing on her Chicago life, where persistence and good intentions came with no guarantees.

Politicians had become expert at turning doubt into fear, she said, as life got “harder, progressively harder, for regular people.”

“We’re still a nation that’s a little too mean,” Obama said. “I wish mean worked, because we’re good at it. Our tone is bad and we’ve grown to believe that, somehow, mean talk is tough talk . . . and we reward it. Not just in politics, but we reward it in every sliver of our culture. We look on people who are tough and say, ‘That’s what we need.’ ”

Obama spoke those words in South Carolina in January 2008. As Trump makes his way to Washington with his gilded pitchfork, her assessment rings true for more than 62 million Americans who supported him and millions more who didn’t care enough to vote. She is leaving the White House with work unfinished and fresh troubles brewing. She was right that day at Mary’s Center, in her first weeks on the job, when she offered a verdict that applied as much to the nation as to herself. There are no miracles, no magic dust.

What Obama offered was something else. To audiences great and small, she presented conviction, savvy, a dose of inspiration and a certain faith that the battles were worth waging and the effort would pay off in the end.

Peter Slevin, a former Post national correspondent, is the author of “Michelle Obama: A Life.”