It's no great secret, so let's just say it: Rachel Roy got her big break in fashion from her husband, Damon Dash, cofounder of Rocawear clothing. Before the couple started dating in 1998, Roy had worked in retail sales, as a personal shopper and making clothes for a handful of clients with the help of a dry cleaner's seamstress. But within two years of meeting Dash, Roy had become creative director for Rocawear's women's and girls' lines. Still, she insists that she was well on her way even without Dash's help. "It may have taken a lot longer," she admits, "but I would have figured something out."

If Roy, 32, can be so forthcoming about the early leg up, perhaps it's because she now stands so squarely on her own. Two years after leaving Rocawear to launch her eponymous label, Roy plans to open the first Rachel Roy boutique (in Manhattan's increasingly trendy TriBeCa neighborhood), where celeb fans like Jessica Simpson and Jessica Biel will be able to browse the racks of her ultraladylike designs (think trench coats with laser-cut leather rose details and softly draped shirtdresses). "I have enjoyed watching Rachel redefine the style of the modern working woman," says Iman. "She allows a woman to be both confident and feminine at the same time."

As charmed as the designer's rise may seem, however, it wasn't a straight shot. "I didn't want to flagrantly practice nepotism and I wanted her to learn the business," says Dash, 35, whose hip-hop empire, Damon Dash Enterprizes, includes movies, music and even a vodka brand. So how did he start Roy on the path to designer? By having her first toil as an intern in various departments—including the mail room. As she wryly notes, "I still know which FedEx stays open late!"

That wasn't the only challenge Roy had to conquer. When she decided to branch out on her own, Roy had to transform herself from a designer who had spent her entire career at Rocawear—a mass line best known for baggy jeans and oversize sweatshirts—to one behind a sophisticated, high-end label. What helped make the leap was the strength of her new product. "People could look at Rocawear and know it was Rocawear, and then look at Rachel Roy; the sensibility is very different," says Roopal Patel, senior fashion director at Bergdorf Goodman, one of the first stores to carry the line. "We just liked what she did."

Her secret, Roy explains over lunch in her mid-Manhattan studio, is that she starts each collection by thinking, "What do I want to wear?" That usually leads her to clothes that are "flattering, wearable, movable," she says. "Very June Cleaver, but with a twist."

Makes you wonder, did her own mom wear pearls while vacuuming, like Mrs. Cleaver? "I wish!" she says, laughing. When she was growing up in beachy, casual Seaside, Calif., her parents, an Indian-born sociology professor father and a U.S. Navy computer consultant mother with Dutch roots, cared "not at all" about clothes. "We couldn't afford much," says Roy. But on grocery day her mom, Ruth, would treat her to a copy of Vogue, and by the age of 14, Roy had a job folding clothes at the mall chain Contempo Casuals. (She lied and said she was older so they would hire her.)

At the time Roy's parents worried about her fondness for fashion. "My mom would tell my dad, 'She'll grow out of it,'" Rachel recalls. "But I didn't." Quite the opposite: Today, her long-term vision includes expanding into lingerie, accessories, fragrances and home products. No wonder then that Dash—whose company owns his wife's label—insists, "She does more for me than I do for her. She really validates me in the fashion world."

He, in return, is able to provide her with a distinctly male perspective. Take his major contribution to her new boutique: He's asked for a flat-screen TV on the sales floor. "Damon said, 'Trust me, the guys will want to sit down!'" Roy explains.

Now if he could only persuade her to take a family vacation with their daughter Ava, 7. Working alongside a staff of only 11, Roy is putting in long hours finishing up her next collection and preparing to open her shop. "Ava calls me every night to ask, 'When are you coming home?'" laments Roy, who has cut back on social engagements so she can eat dinner with her daughter as often as possible. "I hope I'm teaching her what my mom taught me. It's about working hard and creating something for yourself."

When it comes to those pursuits, Roy has no bigger supporter than Dash. "I've always loved her sense of style," he says. "But I didn't realize that lying in the bed next to me was a superstar!"

  • Contributors:
  • Allison Adato/New York City.