The billionaire who single-handedly changed how America shops has an inner sanctum as enigmatic as he is: the corner of a nondescript office building in Columbus, Ohio, across the road from a garbage dump, behind a security gate festooned with “Do Not Enter” signs. While the communal spaces are properly blinged-out with pink walls, lacy bits of lingerie and a big screen rolling endless tape of nearly naked supermodels, the chamber itself is a confused mess of binders and papers straight out of The Absent-Minded Professor. Nearly every surface is devoted to knickknacks–a 3-foot-long pencil here, an Ohio State Monopoly board there–or stacks of books.

The irony seems lost on Leslie “Les” Wexner, who built Victoria’s Secret, Pink, Express and The Limited into one of America’s alltime great retail fortunes. “When I was a kid, before my first store, they talked about stores as theater and retail as theater. It still is,” says the 77-year-old, attired casually in gray slacks and a blue oxford. “Retailing is a free form of entertainment.”

Yet this impresario shuns the spotlight. He’s the CEO of a large publicly traded company, yet he rarely speaks on earnings calls. One of the legends of his industry, yet he almost never speaks to the press. Wexner is so elusive that most assume the brains of Victoria’s Secret is surely some female visionary in the mold of a Sara Blakely or Tory Burch, or else a Hugh Hefner lothario type.

In reality Wexner–net worth: $6.2 billion, good enough to make No. 80 on The Forbes 400–is an introspective guy who has been questioning his every move for decades. His professional success results from a compulsive restlessness and dissatisfaction that steer him away from the herd. His first great insight was focusing on a few products (The Limited) at the apex of the department store age. He expanded nationally when the biggest retail stores were regional concerns. When most competitors rushed overseas, he held back. And in his biggest score of all, he reimagined the lingerie business as a wholesome enterprise that could thrive next to the food court and the multiplex, rather than the boudoir and the peep show.

Being a chronic contrarian is not easy. About to open his first store at age 26, Wexner woke up screaming every night. In his 30s he was a distraught millionaire, searching for a purpose greater than adding more zeroes to his net worth. The money came easier than the fulfillment, and by his 50s he was running more than a dozen businesses, five of them doing sales of $1 billion or more. Then, characteristically, he decided he had it all wrong and from 1998 to 2007 spun off or sold The Limited, Limited Too, Abercrombie & Fitch, Express, Lane Bryant and Lerner New York. He kept Victoria’s Secret, betting that the brand’s emotional resonance would support higher margins in an increasingly commoditized apparel space.

“What I worry about is a fear that you won’t have the idea or that you have figured it out wrong,” he says.

Wexner now owns the only three bra labels that matter: Victoria’s Secret, Pink and La Senza. Together they make up 41% of America’s $13.2 billion lingerie market. Their next closest competitor, if you can call it that, has a 1% market share. Bath & Body Works, the world’s largest beauty retailer, is his, too. He holds all of them under his thriving parent company, L Brands.

L Brands’ 2,949 wholly owned stores sell over $11 billion worth of bras, panties, soaps and other such products a year. Same-store sales have increased in each of the last 19 quarters. Brilliant marketing, especially the annual Victoria’s Secret Fashion Show , accounts for some of this success. But in the disembodied era of e-commerce, hands-on customer service matters, too. Shoppers can buy quality T-shirts and pants from a multitude of different retailers, both online and off, but bras are different. Eighty percent of women in America wear the wrong-size bra. Computers can’t measure them for a proper fit, and employees at, say, Target won’t. But Victoria’s Secret workers do, and women pay the company back with loyalty. Ninety-nine percent of L Brands stores turned a profit in 2013, and Victoria’s Secret’s operating margins are 17%, triple the industry average. In defiance of e-commerce evangelists, he opened 50 new locations in the last year. His online business is not the focus, but it’s doing just fine, accounting for $1.5 billion of his annual sales.

Those numbers have translated into huge gains on the stock market, where L Brands shares have shot up 11% in the last year, twice as much as the S&P retail index. Over the last five years L Brands shares have returned nearly 500%, more than almost any other retailer in North America (the two exceptions: Under Armour and G-III Apparel). “They’ve done such an unbelievable job dominating the market,” says Wells Fargo retail analyst Paul Lejuez. “I can’t think of anyone who has been more successful.”

And there are billions more waiting for Wexner outside of America’s borders. Victoria’s Secret is already famous around the world, not because of its stores but because of its scantily clad models, who hail from every continent except Antarctica. Viewers tune in from 192 countries around the world to watch the Victoria’s Secret Fashion Show on TV each year.

Yet Wexner has barely begun expanding Victoria’s Secret stores worldwide. “Our priority is our domestic business, but we could see that our international business could be as big or even bigger,” Wexner says. In 2012 Victoria’s Secret expanded its wholly owned stores beyond North America, opening two locations in London. Five more stores have since popped up in the U.K., and together they’re already grossing over $100 million.

Wexner is also taking the brand into Asia and the Middle East through a new franchise model, with virtually no risk for L Brands. Wexner has more than 600 franchised stores around the world. L Brands invests no capital in the stores and is virtually guaranteed to turn a profit from day one, charging an outsized royalty of between 10% and 15%. The opportunity is big enough that, for the first time ever, Wexner is moving the Victoria’s Secret Fashion Show outside of the United States, taking it to London this December. “They’re only scratching the surface of international expansion,” says Matthew McClintock, retail analyst at Barclays, who envisions a $10 billion business overseas within a decade. “It’s a gold mine.”

WEXNER’S REFLEXIVE questioning drew him into retail in the first place. After getting his undergrad degree at Ohio State in 1959, he dropped out of its law school and returned home to help around the small family store, Leslie’s, named after him. When his father left on vacation, Wexner tried to solve the riddle of why his dad had always worked so hard but never made any money. He found a stack of invoices, and on a piece of scrap paper began tallying the cost and profit from each item in the store.

The numbers added up to a counter-intuitive conclusion. Although big-ticket items like dresses and coats looked like they had huge margins, they actually made no money because they sat on racks forever. All of the store’s profit came from less glamorous items like shirts and pants. Wexner’s parents returned home to find that their son, with nearly no professional experience, thought he could run their store better than they could. Wexner told his dad to take out the coats and replace them with more blouses and pants. His dad told him to get a job.

He did, founding a rival store to his father’s with a $5,000 loan from his aunt in 1963. He put a limited selection of clothing in the store–only the shirts and pants that flew off shelves–and named the place The Limited. Wexner signed a lease for a second store before even opening his first, convinced that if the idea worked in one store it would work in another. Before selling a single shirt, he already owed his landlords $1 million. He had nightmares every night and eventually started getting belly pains. The doctor told him he was too young to have a stomach ulcer, but the X-ray clearly showed the hole that fear had eaten through his stomach.

He made $20,000 of profit in his first year, twice as much as his dad’s best. The secret was his focus on only a few products, a revolutionary idea at the time. Wexner says that Steve Jobs (or presumably it was Jobs–”what’s-his-name from Apple,” Wexner says off-handedly) was one of many to credit The Limited boss with inventing specialty retail. “Probably did,” he shrugs.

Curious about how far his idea could take him, Wexner bought a U.S. map and a compass. He drew a circle to see everywhere he could get from Columbus in a day. Commercial airlines had just started using jets in the 1950s, significantly extending the radius of Wexner’s compass and bringing 70% of the U.S. population within two hours of headquarters. Leveraging his centralized location and jet travel, Wexner decided he could build a national chain. By 1973 Wexner was well on his way, with 41 stores selling $26 million worth of pants, skirts and blouses.

Having proven that narrowly focused stores appealed to female customers, he set about creating new companies, built in The Limited’s mold. He launched Express in 1980, targeting younger women with more colorful, casual clothes. And he also got curious about a small chain of lingerie shops he had seen in San Francisco called Victoria’s Secret. He never could find out much about them because their owner, Roy Raymond, clammed up every time Wexner started to ask questions. But in 1982 Raymond called up Wexner and finally wanted to talk. Raymond was on the verge of bankruptcy and was hoping Wexner would buy his six stores before the sheriff took them. “I literally flew out that afternoon and met him in the evening and bought the business,” says Wexner. “I didn’t know anything about it.”