Kristen Jarvis, Michelle Obama's 'Little Sister'

Renegade, Renaissance, Radiance, and Rosebud, better known as the Obamas (Barack, Michelle, Malia, and Sasha, respectively), were off on Marine One, which meant Kristen Jarvis could relax, briefly. Moments after the first family were whisked off to their vacation in Martha's Vineyard, Jarvis, whose title is special assistant for scheduling and traveling aide for the first lady, took a breather at her East Wing office. Through her indefatigable smile, she ticked off the items that Michelle Obama needed on the presidential campaign trail last year: several Sharpies, her BlackBerry, Oreo cookies, and hand sanitizer. "There's no time to get sick," says Jarvis, referring to her boss and herself. "You're on call."

Being a young, African-American woman overseeing the affairs for the first black first lady in the White House has its unique, historical responsibilities. During the grueling campaign year Jarvis spent with Mrs. Obama, that meant a shared spreadsheet for black hair salons from Las Vegas to Chicago. "Hairdressers in every state!" she laughs now. "It was a struggle."

Just as "Obama's cooler little brother", Reggie Love knows a thing or two about the president and his needs, Jarvis knows her fair share about the first lady. She calls Michelle "a big sister."

"I worried a lot about the first lady as the campaign continued and as all of our lives changed," said Mike Strautmanis, senior Obama adviser Valerie Jarrett's chief of staff and Jarvis's former boss from Obama's Senate office. "I wanted her to be around people who I knew would take care of her; and Kristen, I knew, would take care of her."

The effervescent 28-year-old is a graduate of Spelman College, a prestigious historically black women's college. Her history with the Obamas has given her insight into the couple and a unique vantage point to help the first lady make the transition from Chicago to D.C. "It's change for them," says Jarvis, who has introduced the first family to some of her favorite eateries around Washington. "Change is good. She's very low maintenance. I think just being here together makes all the difference in the world."

The 2004 election cycle was a blessing in disguirse for Jarvis. A staffer for Senate Majority Leader Tom Daschle, her political world collapsed that November when her boss was bounced from Congress and George W. Bush won reelection. That's when Pete Rouse, Daschle's chief of staff and now a senior White House adviser, brought her into the office of a young senator from Illinois named Barack Obama. In those days, "We always knew," she says now. "We always believed that if there was going to be a first African-American president, he was going to do it."

Jarvis served as scheduler in Nevada and on the press advance team for the Obama campaign before joining Mrs. Obama for the general election. "Literally, I was in a different state every week," she says. "A lot of it was just making it work with the resources that we were given."

That, too, has changed completely from the Senate days when Obama flew coach to Chicago. Today, when the first lady wants to jet to Copenhagen with Oprah Winfrey, transform the East Room into a Stevie Wonder concert, or import 650 pounds of Hawaiian pork butt to the South Lawn of the White House for a luau, Jarvis and countless others are right there to make it happen.

Mrs. Obama has a personal aide, Dana M. Lewis, in the residential part of the White House. But once she steps out of the White House, Jarvis is at the first lady's side. When Mrs. Obama decided to take a tour of government agencies including the departments of education, agriculture and veterans affairs—introducing herself to the neighbors, as it were—Jarvis was there to see the stunned looks on the faces of career employees. "It was refreshing," she recalls. "A 'thank you' goes so far, and to have it come from the first lady is just great."

Some of her fondest memories with the first family so far include their trips abroad. "Ghana was the most humbling experience of my life," she says. "Just to see people on the other side of the world so excited about this first family, it was almost numbing." The recent jaunt to Copenhagen, to make the case for Chicago hosting the 2016 Olympics, was bittersweet. "I haven't cried at one of her speeches in a while, but this one brought me close to tears," she says, of Mrs. Obama's presentation for her hometown's failed bid. "It was a tough week."

Despite managing East Wing affairs, her influence extends to the West Wing, as well. In Obama's Senate office, Jarvis hired Joshua DuBois, now executive director of the White House faith office, and junior staffers John Oxtoby, Karen Richardson, and Amanda Brown—who now work under Jarrett, health-reform director Jeanne Lambrew, and political director Patrick Gaspard, respectively. "I've come to admire her," says Strautmanis. "She has a maturity that is uncommon not only for someone of her age but just for anyone."

Jarvis has been with the first lady for some of her most memorable moments before and after her husband's election. On the first day of the Democratic National Convention in Denver, Jarvis watched her boss pace the floor as she practiced for one of the most important speeches of her life. Election night was another experience entirely. She and Love were shepherding the family through the doors of the Hyatt hotel in downtown Chicago. "When we got to the hotel, I think they had just called Virginia," Jarvis recalls. "Right after [Obama] gave the speech, I said 'Congratulations, senator,' and I stopped because I was wrong. I looked back and he gave me a look like, 'Wow, I am the president.' "

Now that the entire team is in Washington, things haven't changed too much. Michelle is still mom in chief. "First and foremost her main priority is taking care of the kids. A lot of our life depends on what they're doing," says Jarvis. But the campaign days of snacking on chips and cookies are over. "She's on this healthy kick now. She's over Oreos."

Perhaps Michelle Obama is worried about practicing what she preaches: she has made healthy eating among children her signature issue, and Jarvis is working with her on that. A stack of health-conscious food writer Mark Bittman's cookbooks litter the East Wing. Glossy photos of Mrs. Obama bending and planting in the new White House kitchen garden hang next to iconic images of her holding a Bible for her husband on Inauguration Day. At a Healthy Kids Fair last week with a crop of schoolchildren, Michelle Obama sampled zucchini quesadillas and baked apples prepared by visiting chefs. When it was time to remove her wireless microphone for hula-hooping and double-dutch, Jarvis trailed behind, repositioning the first lady's favorite Azzedine Alaïa belt.

The hours are long for a White House job as intimate as Jarvis's. But over the five years they've worked together, the Obamas have become like a surrogate family to her. Jarvis has lost both of her parents in the last decade. When her brother passed away last year, the president called her cell phone directly. "It was the North Carolina primary night, a big day. And he took the time to call me. The first lady called me," she remembers. "There's a million and one staff members and you take the time out of your day. That's why I'm here. I work for great people."