Michelle Obama will bring the skills of a corporate lawyer to the White House if her husband wins the US presidency, but she says her priority will be her role as "mom-in-chief" to the couple's daughters.
Democrat Barack Obama faces Republican John McCain in Tuesday's election. If the first-term Illinois senator wins, he will become the first black US president and his wife the first black First Lady.
Michelle Obama, 44, is a passionate advocate for her husband's candidacy, but she says she would not want a direct policy role in an Obama administration.
"My first job, in all honesty, is going to continue to be 'mom-in-chief,'" she said in a recent magazine interview refering to daughters Malia, 10, and Sasha, seven.
She also says she hopes to focus ways women maintain a work-family balance and the needs of military families, and she could act as an informal adviser to her husband as she has been during the campaign.
Obama, who grew up in a blue-collar neighbourhood on the south side of Chicago and went to public school, often talks about her father - who worked for the city's public water system - and the values instilled by her parents.
After winning scholarships to the elite universities of Princeton and Harvard law school, Obama worked for a law firm and in the Chicago mayor's office.
Her most recent job was vice-president of the University of Chicago hospitals, where she earned more than her husband. Even though the Obamas are now well off, partly due to royalties from Barack Obama's two books, Michelle Obama stresses the values she learned growing up.
"When you are raised in a home ... (in which) you have love and security and you have people who are sacrificing for you ... you have an obligation to give back," she said. "That's why community service has been such a big part of my life."
Barack Obama describes his wife as his "rock", a source of strength and a gentle critic who keeps him grounded. Their public displays of affection and her fashion sense - she has been featured in magazines such as Vogue and Essence - contribute to the candidate's youthful image.
In a widely praised speech at the Democratic National Convention, Michelle shared details of the couple's life together and said her husband represented typical American values.
"What struck me when I first met Barack was that even though he had this funny name, and even though he'd grown up all the way across the continent in Hawaii, his family was so much like mine," she said.
"He was raised by grandparents who were working-class folks like my parents, and by a single mother who struggled to pay the bills just like we did."