From Serving in Iraq to Welcoming White House Guests

“How long was your confirmation hearing?” Mr. Holder asked with a smile.

“You want to say, ‘Hello, Potus,’ ” Ms. Page said later, recalling her interactions with Mr. Obama, who picked up the Rotus nickname from young aides and now uses it nearly every time he sees her. “But then you say, ‘Hello, Mr. President.’ ”

Ms. Page presides over the beehive of activity that is the West Wing lobby of the White House. At 27, she is among the hundreds of young aides who help the new administration tick. But her vantage point offers a considerably closer view of this presidency than most of them.

She is on hand to greet nearly every official visitor who has an appointment with the president or his top advisers. She oversees the front of the house at 1600 Pennsylvania Avenue, serving coffee to former Prime Minister Tony Blair of Britain, making small talk with a delegation from Kazakhstan and trying to chew a mouthful of almonds quickly before saying hello to Tiger Woods as he stands at her desk.

“I tried not to be very star-struck,” Ms. Page said of the golfer’s recent visit. “I’m usually not, but I was caught completely off guard. All of the people that come in, I think, are humbled by the office, so they are all very nice.”

Last week alone, the list of visitors ranged from Harry Reid and Mitch McConnell, the Democratic and Republican leaders of the Senate, to the actors Owen Wilson and Ben Stiller, in town for the domestic premiere of their movie, “Night at the Museum: Battle at the Smithsonian,” at the Smithsonian’s Air and Space Museum.

Ms. Page tries to memorize the faces of the senators and representatives who come to the White House. But after a guest passes through the security gate on the North Lawn, she has approximately five minutes to do a Google search if they are unfamiliar, all so she can make small talk during their inevitable wait.

The White House, at least the portion of it where the president’s official business is conducted, is smaller than it looks on television. If the three sofas and half-dozen chairs in the West Wing lobby are filled, visitors must stand as if they were in a waiting room at a busy doctor’s office — although one with better artwork, like the 1861 oil painting “Cannonading on the Potomac” by Wordsworth Thompson that hangs above the receptionist’s desk.

“Hi, how can I help you?” Ms. Page said in greeting a visitor on a recent morning as men and women in business suits milled around. “Are you here for Nancy? You can have a seat.”

For her $36,000-a-year salary, Ms. Page schedules all the activity in the Roosevelt Room, just steps from the Oval Office, and in the Wardroom Room, which is outside the White House mess hall. Even with a dawn-to-dusk schedule, the meetings often run overtime, creating a logjam that she is left to contend with.

One sign of a busy day? An ever-growing pile of BlackBerrys and cellphones.

The Roosevelt Room is secure, so she must collect all personal electronic devices at the door. She uses yellow Post-it notes to write the last name of the owner on each device before placing it in a wicker basket on her desk, next to a vase of fresh flowers that is rotated at least every three days.

Her path to the White House began in a bar in downtown Chicago, where she and a group of friends from the University of Illinois stopped by for happy hour and dinner one night in fall 2007. A man in a “Veterans for Obama” shirt was sitting nearby, and they began talking about the campaign. Soon, she was a volunteer. A few months later, she was hired to work in the operations department to make travel arrangements and handle logistics for campaign field workers and senior strategists.

“You can tell a lot about a person’s temperament based on how they travel and what they’re willing to take and what they’re not willing to take,” Ms. Page said. “It helps dealing with them now.”

This is her first White House job, but Mr. Obama is the second president she has served. The first was George W. Bush, her commander in chief when she was an Army sergeant stationed in Iraq.

Ms. Page joined the military after finishing high school in Maryland, following a long line of others in her family. She worked as a paralegal in Baghdad, taking depositions in the Abu Ghraib prison. She still wears a metal bracelet on her right wrist inscribed with the name of Sgt. Maj. Cornell W. Gilmore, her commander, who was killed when enemy fire struck his helicopter in late 2003.

“He taught us to lead, but to lead with a smile and be calm under pressure,” she said. “A lot of lessons that I learned in the Army help me here. There is a lot that goes on that I have to do with a smile even if I really don’t want to.”

A task that requires particular diplomacy is overseeing the presidential boxes at the Kennedy Center for the Performing Arts. A few days a week, she goes to pick up tickets and checks to be sure that the V.I.P. seats in all three theaters are in order and that the minibar is stocked with small bottles of Korbel champagne, white boxes of M&Ms with the presidential seal on them and a few cans of Bud Light.

The next challenge? “The Color Purple” is playing this summer, and requests far exceed the number of seats at Ms. Page’s disposal. As she walks down the center’s grand hallway, where coming performances are advertised, another worry pops into her mind.

“I’m dreading ‘Peter Pan,’ ” Ms. Page said, hurrying back across town to the White House. “Oh, Lord.”