Former Coke exec Laurie Ann Goldman was the powerful brand builder behind SPANX founder Sara Blakely’s billion-dollar success.

FORTUNE — SPANX announced yesterday that the CEO Laurie Ann Goldman would be leaving the Atlanta-based company. Despite the surprising management change, Goldman’s success with the brand is undeniable.

While on maternity leave in 2001, Coca-Cola licensing exec Laurie Ann Goldman perused Saks Fifth Avenue in Atlanta in hopes of scoring a pair of fishnet tights made by fledgling startup SPANX. Her size was continuously sold out. Goldman visited the department store three times, and she felt so exasperated that she questioned the salesperson about the company’s supply-side management.

Goldman’s chastisement caught the ear of SPANX founder Sara Blakely’s then-boyfriend, who was also the COO and happened to be on location that day. He exchanged numbers with Goldman. She went on to advise the hosiery company casually — and the following year, she joined as its CEO.

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Today, SPANX products, from open-toed pantyhose to slimming bodysuits to back-smoothing bras, are ubiquitous — in more than 11,500 locations including SPANX stores, on celebrities like Oprah and Gwyneth Paltrow, and on the runway at New York Fashion Week. SPANX sales reached a reported $250 million in 2012, and Blakely, the founder, became the world’s youngest self-made female billionaire.

While Blakely is the bona fide hosiery genius, her brand would never have hit icon status without CEO Goldman’s focused vision. Goldman crafted a business model for the company based on lessons she learned during her 10-year stint at Coke: thinking big, starting small, and scaling fast. She advised her team at SPANX to focus on product quality over profit margins. “Every time somebody puts on a SPANX product, one of two things can happen: Our brand can get stronger, or our brand can get weaker. We gain leverage or we lose leverage.”

Here’s more from Goldman, in my October interview with her about building the brand: