Behind every well-known powerful man or woman is a shadow operative making sure everything runs smoothly.

For Mark Zuckerberg, it's Anikka Fragodt, his executive assistant that's been around for most of Facebook's lifetime.

But for Sheryl Sandberg, it was Libby Leffler, now strategic partner manager at Facebook. She served as a "business lead" to Sandberg for almost three years.

Until she changed positions, she served as Sandberg's invisible hand, ensuring Sandberg could continue running Facebook's business operations without a hitch.

Leffler was a more than competent business envoy to her boss Sandberg. She's "stellar," "delightful" and "extremely smart, and she can turn around a 17-page briefing document, complete with charts and tables, in a half-hour."

Before Facebook, Leffler worked as a strategist at Google in the group Sandberg ran there, Online Sales and Operations. She's a graduate of the University of California at Berkeley's business school.

She joined Facebook in September 2008, about six months after Sandberg left Google to work at Facebook, as a "business lead" to Sandberg.

She now works with public figures and other institutions to partner with Facebook around high-impact integrations, with a specific focus on nonprofits as a strategic partner manager.

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