Meet the guy making shoes for diabetics, vets and P. Diddy

If you've got problem feet—Ken Silverman is your guy. The 73-year-old has spent his entire career at the Bronx-based factory his father founded after World War II, making shoes that cater to such clients as diabetics with ulcers and veterans with prosthetic legs.

But out of that same American Orthopedics plant, lined wall-to-wall with chalky molds of swollen ankles, flat arches and leather shoes that fashion acolytes would scoff at, Silverman has reinvented his own brand. He's now making custom sneakers for the likes of 50 Cent, Justin Timberlake, P. Diddy, Beyoncé— even an Arab sheik.


Custom shoemaker Ken Silverman.
Kate Rogers | CNBC
Custom shoemaker Ken Silverman.

Two years ago, Silverman's son Jon, who worked in bespoke shoe design in Manhattan in addition to his work at the family business, persuaded his dad to take a look at the high-end sneaker market. Ken says the technology he needed to make the switch was conveniently already in place at the facility—the same machines that make clunky orthotics also work for refitting Nikes with exotic leathers like ostrich and snakeskin.

"It's the intricate stitching and the ability to perform that has allowed us to make this segue," he said, adding that his new venture, Relevant Customs, accounts for about 20 percent of his business, and the original manufacturing venture makes up 80 percent.

Worker making custom shoes
Betsy Cline | CNBC

For any naysayers out there, the basketball sneaker market is booming. Market research firm Janney Capital Markets reports basketball footwear sales were at $4.2 billion in 2014 in the U.S. alone, citing data from SportsScan, a consumer insights firm. Janney predicts sales will increase by 12 percent to $4.7 billion in 2015—and price tags on sneakers can run into the hundreds and even thousands before a designer like Silverman gets his hands on them.

Relevant Customs got one of their first pairs of sneakers onto Jay-Z through a company called Pimp My Kicks, which has since gone out of business. The rapper was photographed wearing them at a basketball game with his wife, Beyonce, and business took off from there. Silverstein gets his business mainly through word of mouth, dealing with stylists to the stars. The new shoes retail for much more than the orthopedics, which range from $800 to $1,000. The high-end sneakers cost anywhere from $1,800 to more than $10,000.

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But each day, the facility is churning out about 100 pairs on the orthopedic end, but only about one pair of the sneakers, since they are more design-intensive.

"We had a routine, stodgy business that had been around for a long time," Silverman said. "Now all of a sudden, life is completely different because we are dealing in a fashion world that I didn't know much about, and in a new fun area of commerce that is very intriguing and exciting."

Relevant Customs is now embarking on a new journey, creating an original line of shoes that will retail for up to $1,000.

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He says the success of the new venture, which is on track to turn a profit this year after just two years, has taken him by surprise. But more importantly, it's fun.

"If you asked me if I would have believed this two years ago, I would have said no," he said, "but now I race to get to work every day."