Sheryl Sandberg's greatest career lesson

Facebook COO Sheryl Sandberg has become the go-to adviser for aspiring young women in business. Her view, which she expressed in an on-stage interview with me at the recent Fortune Most Powerful Women Summit: "Women don't take enough risks. Men are just 'foot on the gas pedal,'" she said, adding, "We're not going to close the achievement gap until we close the ambition gap."

Indeed, Sandberg's own career path--from the U.S. Treasury to Google (GOOG) to Facebook--is distinctly marked by risk-taking and counter-intuitive turns. Instead of taking the safe senior job at some boring big company, she went for speculative but potentially big growth opportunity. "When I went to Google," she told the Summit audience, "Google was like 250 people. I was going to be a business unit general manager, except there were no business units...This was the non-job of all time."

What gave her confidence to make the leap? "Growth moves everyone up," her recruiter, then-CEO Eric Schmidt told her. "If it's growing, it works."

And while Sandberg, No. 12 on the Fortune Most Powerful Women list, now looks like a genius for jumping to Facebook to be CEO Mark Zuckerberg's No. 2, in 2008 she seemed crazy, as she acknowledged in the interview: "A lot of people asked me, 'What are you doing? You're going to work for a 23-year-old? No one knows if Facebook is going to be the next MySpace or Friendster. And you're not CEO. You could be CEO somewhere else.'

Her own career lesson: "At each stage, I cared less about my level," Sandberg said, adding that women, especially, "are too worried about the upward trajectory and not enough about growth." Here's more advice from Sandberg on building a great career:

Click here to read the full transcript of my interview with Facebook's COO--and read what she says about a career turn many believe she might take someday: running for political office, even governor of California.