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Mellody Hobson has a slate of corporate board seats that many a star executive would envy: She is a director at Starbucks (SBUX), Estee Lauder (EL), Groupon (GRPN) and DreamWorks Animation (DWA). And while her day job is serving as president of Chicago-based Ariel Investments, Hobson is also non-executive chairman of DreamWorks—as well as one of CEO Jeffrey Katzenberg's most trusted advisors.
How did Hobson get such plum corporate gigs? For one thing, the 44-year-old executive knows what she's good at—and not. "We say at Ariel, 'What is your towering strength?" Hobson said in an interview with Katzenberg for Fortune's "Best Advice I Ever Got" package. She and DreamWorks' chief agree that her towering strength is simplifying complicated information and explaining it well.
Genius, said Einstein, is taking the complex and making it simple. Hobson is no genius--just a smart executive who focuses well to guide bigwigs. "Don't major in the minor," she says. Katzenberg says this is his favorite advice from her. Hobson also subscribes to the investment philosophy of Warren Buffett and Charlie Munger (also featured in the "Best Advice" package) who hunt for haystacks—clear, explicable, durable winners like Coca-Cola (KO)—rather than obscure needle-like plays.
Vetting investment opportunities for the companies whose boards she sits on, Hobson keeps in mind: "If it grows like a week, it is a weed." The challenge for any company, she explains, is: "How do you get in the oak business?"
Long-term thinking has paid off for Hobson, career-wise. "When I walked in the door at Ariel at 22," says the '91 Princeton grad, "I thought, 'I'm going to walk through this door thousands of times.' I've worked at one place for 22 years. I'm the only person from my graduating class at Princeton who still has the same work number."