Michelle Obama said her husband always chooses principle over power.
"Barack could have been a CEO, but he wanted to be a community organizer," she said.
She noted that he was the first African American president of the Havard Law Review.
"To whom much is given much is expected," she said.
She noted that Obama was in the Illinois legislature for eight years.
"His opponent cannot boast that kind of experience."
He's also tough enough to win a general election, she said, pointing out that his political experience was built in Chicago.
"Barrack got a lot done most of the time working in the minority," he said. Even so, he helped make major changes on healthcare, death penalty laws and ethics, she said.
"Imagine a president of the United States who has the power to unite people around issues," she said.
It was so-called experienced politicians who led the United States into the Iraq War, she said.
"All of them marched us into a war that should never have been authorized and never waged," she said.
When he took a stand against the war, Obama was in a "tough" seven-way bid for his Illinois Senate seat, she said.
"They said he was too young. They said he was too inexperienced," Obama said. "They said he was too black. They said he was not black enough."
They also used a "fear bomb" by saying that Illinois residents would never vote for him because of his name, she said.