Michelle O: the US 'mom in chief' who gets the last word

It ends an extraordinary personal journey which has taken the 45-year-old from her native Chicago to the side of the most powerful man in the world.

From tomorrow, she is official consort, prime symbol of American womanhood, fashion advocate, matriarch and comforter of the nation.

There's a certain poetic justice here for a woman of fiercely progressive views, whose doctoral thesis at Princeton was on the sense of dislocation faced by America's black graduates, once they moved into predominantly white professional life: Mrs Obama always wanted to succeed, but has been more openly aware of her racial background than her husband. "As black as it gets," is how she once described herself.

She has her own career achievements, as a commercial lawyer and later running a major health trust in Chicago, where she met her husband when he worked as an intern at the same law firm.

All that is parked now in the pre- presidential past. She is aware of the transition, routinely describing her intended role as "mom-in-chief," and emphasising that it her husband, not her, whom the voters have elected.

So, no Hillary Clinton-style muscling into major government programmes, or insistence that she won't be the "little woman... baking cookies".

Those who know her well, however, say Mrs Obama will not be content to model those now-famous shift frocks, without a more substantial role. "She's not Jackie O, she's Michelle O and that's a big difference." says one member of her husband's team.

He says her focus on women's health is one of her main preoccupations. "I'd be surprised if she didn't use her platform to do something big on this," he added. "She knows she is the ultimate role model and she won't waste that opportunity."

Team Obama is, however, extremely wary of Mrs Obama being seen only as the First Lady of black or ethnic minority America. They did not craft a message of healing division only to start up new ones.

So the new First Lady will strive to be inclusive: already she has formed an unlikely friendship with Laura Bush, who also championed literacy for the poor, and has been discreetly talking to her about the upheavals of White House life and their impact on family life.

Changes have been made along the way. Michelle's grooming is now near faultless, her gangly limbs toned by workouts.

She does not joke, as she did artlessly at the start of the campaign, about her husband's snoring. Her one gaffe - about only being proud of her country when her husband received the nomination, was never repeated. "She didn't need anything to be said about it," says Mr Obama's chief strategist David Axelrod diplomatically.

A "no new friends" rule was imposed to prevent the Obamas falling prey to opportunistic new intimates who might spill the beans or prove embarrassing.

Chicago friends say she replicates much of the loving strictness of her own upbringing. Her father - a clerk of works who suffered from multiple sclerosis - would chide Michelle by saying merely: "I expected so much of you, and now you've gone and disappointed me."

It's exactly the same phrase she uses when her own girls misbehave. "She has incredibly high expectations of herself and other people," says someone who knows her well.

Her anxiety about the impact of her husband's transition on their daughters is palpable. She complained about his long absences from home when he was running for Congress and is still apt to emphasise the number of full days he has spent at home since the presidential bid began - 10 in total.

It was all worth it in the end. The Obamas make history tomorrow as the first black couple in the White House.Who has the better sense of humour? an interviewer asked the new president recently. "She does," said Obama.

"And who has the last word?" He didn't even hesitate, "She does." Now that will be interesting.

Superwoman with humble origins

Age: 45

Childhood: Born in Chicago to Fraser Robinson, a water plant employee, and Marian Shields Robinson, a secretary. Brought up on city's working-class South Side. Brother Craig is a basketball coach.

Education: Studied sociology and African American studies at Princeton, then Harvard Law School.

Career: Marketing and intellectual law at Sidley Austin. Later associate dean at the University of Chicago, director of Chicago Council on Global Affairs, the University of Chicago Laboratory Schools and Tree House Foods. Finally, vice president for external affairs at University of Chicago Hospitals.

Family: Married Barack in 1992. Two daughters, Malia, 10, and Sasha, eight.

Style: Known for her love of sleeveless A-line dresses and high-street bargains but black and red number on night of her husband's victory was poorly received.

Good times: First black First Lady after a largely gaffe-free campaign.

Bad times: Father had multiple sclerosis for much of her childhood.