(CNN) You will see them on catwalks, red carpets and on high streets all over the world -- a shoe that fits as comfortably on the feet of celebrities as it does on those trundling around shopping centers on a Saturday afternoon.
For many, though, the name stamped on the iconic sports shoe remains something of a mystery -- despite being a two-time grand slam singles champion.
"I did some interviews in Paris a couple of years ago ... one person said: 'I think he played basketball.' Another one said: 'maybe he played tennis, or was he a runner?'" the 69-year-old Stan Smith told CNN's Open Court.
"Some people say to me 95% of the world have no idea who you are and then my wife jumps in and says '99% of people in the world have no idea -- as a person.'"
While Smith's exploits on the tennis court may have lost in the mists of time, his eponymous shoes have lived on in the public consciousness selling more than 40 million pairs for the German sportswear company Adidas -- their bestselling shoe of all time.
"Players used it (at that time) because it was the best tennis shoe," Smith explains, "but it is now a fashion and I'm a fashion icon. It's crazy!"
Smith emerged as a force in world tennis in the late 1960s, enjoying a stellar career that straddled both the amateur and Open eras.
In all, he won seven grand slam titles (two singles and five doubles), 100 tour titles and seven Davis Cups for the US, including a run of five wins from 1968 to 1972.
He was also the first man to win the season-ending ATP Tour Finals when it was first held in 1970 -- not bad for a teenager who hadn't made the grade as a ballboy.
"There was a Davis Cup match at the Los Angeles Tennis Club and a group of kids from the Pasadena program in LA were going to ballboy," Smith explains.
"It was a big thrill and obviously I wanted to do it but they decided I was too big and clumsy and I'd bother the players."
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His 6-feet 4-inch frame was less of a hindrance on court and with coach Pancho Segura honing his raw talent, Smith quickly became a potent force in the men's game.
With a rapid serve and a deft touch at the net, Smith's game was suited to both singles and doubles and he soon cemented a place on the US Davis Cup team.
A first grand slam doubles title arrived in 1968 -- partnering Bob Lutz when the US Open was played at Forest Hills -- before making his mark in singles with victories at the 1971 US Open and at Wimbledon the following year.
Victory over Ilie Nastase in front of a packed Center Court crowd remains a career highlight, but so do the Davis Cup triumphs.
"Playing outside your country is the most special because there are very few people supporting you. They play the national anthem, they have the American flag up -- it's incredibly special."
By the end of 1972, and having starred in the US's fifth successive Davis Cup win against Romania -- in front of a baying Bucharest crowd -- Smith had risen to the top of the men's rankings and had the world at his feet.
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It was, perhaps, no surprise that Adidas came calling.
Looking for a marketing replacement for the recently retired French tennis star Robert Haillet, Adidas approached the American.
Today's shoe remains largely faithful to the original design that Smith wore on court.
"The only change would be a little more support on the Achilles tendon at the back of the shoe," Smith says. "Other than that it is the exact same shoe that was designed by Horst Dassler, Adi Dassler's son, and Haillet."
Smith's stenciled portrait and signature still adorn the tongue and remain an essential fashion item for the rich and famous -- with Pharrell Williams and Kanye West paid by Adidas to promote the shoe.
While the celebrity endorsements are flattering, Smith extracts just as much satisfaction from the stories he hears when doing promotional tours.
"Just recently I was in Tokyo and a guy from GQ magazine said: 'You know, I have worn your shoe every day of every year for the last 13 years!' The guy said he had kissed his first girl wearing the shoes," Smith says with a chuckle.
"Another guy said: 'I met this girl wearing these shoes and it meant so much that I got married wearing them!' Stories like that go on and on."
Tennis footwear has moved on and the stars competing in this year's ATP Tour Finals will wear shoes that reflect the rigors of the modern game.
But a sizable number of the spectators filing through the turnstiles at London's O2 Arena later this month will be sporting a pair of Stan Smiths -- most of them oblivious that they are wearing the shoe of the man who won the inaugural tournament in Tokyo 46 years ago.
Back then, Smith received a check for $15,000 and a bottle of Pepsi, who were co-sponsors, but no trophy.
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While Smith is happy to admit that the prize money was "a fortune" in the 1970s it still pales in comparison to the $2.4 million jackpot on offer to this year's winner.
But he refuses to dwell on the disparity.
"You can look at it two ways. "You can say 'jeez, it was terrible that I was in this situation where the prize money was so low.' But before that there was no prize money at all. It was just amateur tennis and you would play for the love of the sport."
Of course, being a modern fashion icon is a status that money just can't buy. But Smith is happy to let his shoes do the talking -- most of the time.
"When I see people wearing them I kind of laugh. Occasionally, I'll go up to somebody and say: 'Do you like the shoe?' and they'll say: 'Yeah, it's a cool shoe!' And I'll say: 'Do you know who he is?' and they reply 'No,'" he says.
"Sometimes I might say something but generally I'll just walk away. That's fun."