The first lady's efforts are mostly private, The New York Times reports. In October she appeared at seven fundraising events and made an unscheduled visit to the Chicago campaign headquarters to chat with young workers.
"Her mission is to energize folks and give them encouragement to go out and do the work," campaign strategist David Axelrod told the Times.
President Obama appears to have an uphill fight in 2012. The stagnant economy, high unemployment and disappointment among many Democrats who find him too cautious or conservative have led to slumping poll numbers.
While Mrs. Obama has been careful to keep campaign talk out of events aimed at pushing the jobs bill or calling for aid for veterans, she has more freedom to be political than her husband, one observer said.
"She has the freedom to be fully passionate," said Marilyn Katz, a longtime Obama supporter who owns a public relations company in Chicago. "There's a kind of constraint that comes with the office, and she can be the unbridled campaigner."