Michelle Obama says she had to fight misperceptions due to her African-American race during the 2008 White House campaign that saw her husband become the first black president of the United States.
The first lady, who grew up in humble circumstances in Chicago and became a successful corporate lawyer, has rarely discussed race during her husband's two terms in office.
But a string of recent cases of alleged abuse of police force against African Americans, and related unrest in Baltimore, made it hard to avoid.
"As potentially the first African-American first lady, I was also the focus of another set of questions and speculations, conversations sometimes rooted in the fears and misperceptions of others," Obama said Saturday.
"Was I too loud or too angry or too emasculating? Or was I too soft, too much of a mom, not enough of a career woman?" she asked in a frank commencement address at historically black Tuskegee University in Alabama.
For the first magazine cover featuring Obama in 2008, The New Yorker parodied her as a radical and a terrorist.
"It was a cartoon drawing of me with a huge afro and a machine gun," she recalled.
"Now, yeah, it was satire, but if I'm really being honest, it knocked me back a bit. It made me wonder just how are people seeing me."
- 'Sleepless nights' -
In an almost half-hour address, she also recalled other racially insensitive comments, including when Fox News television said she was her "husband's crony of color" and "Obama's baby mama" -- the latter US slang for an unwed mother.
"Back in those days, I had a lot of sleepless nights worrying about what people thought of me," Michelle Obama recalled.
"I had to ignore all of the noise and be true to myself -- and the rest would work itself out," she said, winning cheers from graduates.
Aside from mastering details of administration policy, "I also worked to ensure that my efforts would resonate with kids and families -- and that meant doing things in a creative and unconventional way," Obama said.
"So, yeah, I planted a garden, and hula-hooped on the White House lawn with kids. I did some mom dancing on TV... And at the end of the day, by staying true to the me I've always known, I found that this journey has been incredibly freeing."
Frustration, "can feel isolating. It can make you feel like your life somehow doesn't matter. And as we've seen over the past few years, those feelings are real," the first lady added.
"They're rooted in decades of structural challenges that have made too many folks feel frustrated and invisible, and those feelings are playing out in communities like Baltimore and Ferguson and so many others across this country."
But while being a minority in the United States can be tough, she said, it was no reason to lose hope.