Mr. Fieg has been developing his tastemaker status since he turned 13 and asked his second cousin David Zaken, the owner of the David Z chain, for a job at one of his shoe stores instead of bar mitzvah money. He began taking the F train from the final stop on the line, near his parents’ house, to the West Village, after school and on weekends. At the time, the block where he worked, Eighth Street between Fifth and Sixth Avenues, was a gathering spot for some of the decade’s biggest stars.

“On the weekend the cars were parked diagonally on the block,” Mr. Fieg said. “The cops would let it ride.” He ticked off the names of customers who came in while he worked on the floor and in the stockroom: Biggie Smalls, Busta Rhymes, Nas, Missy Elliott, Tyson Beckford, Wu-Tang Clan, the Fugees. “Jay-Z used to come in every Saturday and buy two pairs of construction Timberland boots from me,” Mr. Fieg said. “He would leave his old pairs there and buy two fresh pairs.”

From customers like these, Mr. Fieg would learn about the cool new thing and bring that knowledge back to Cardozo high school. “I’d come in dressed a certain way and get laughed at, and then all of a sudden everybody is wearing the same stuff,” Mr. Fieg said. “New Balance was the thing back then, and they’d be like, ‘Why are you wearing orthopedic sneakers?’ And I’d explain, ‘These are premium, made-in-U.S.A. runners.’”

Mr. Fieg has an intuitive understanding of what his customer wants because in many ways he is his customer. “I want a Bergdorf Goodman varsity jacket, and I want it to be multicolor in these regal colors, and then I make it and I wear it,” Mr. Fieg said. And then his followers wear it, too.

Before he was even a teenager, Mr. Fieg desperately wanted a pair of Reebok pumps, but his parents couldn’t afford them, so his mother bought him a pair of Asics Gel Lyte III sneakers instead. Mr. Fieg was disappointed at first (“I was crying,” he said), but he eventually came to love the shoes and wore them into the ground. When he asked for another pair, it turned out they were discontinued.