Lele Sadoughi has built her business on big, bold, bloom-filled jewels that she proudly calls costume. Wallflowers need not apply.

You might not know Lele Sadoughi’s name, but you certainly know her work. A master of costume jewelry, Sadoughi began her design career at Ippolita, working with private-label clients including Banana Republic and Club Monaco before creating J. Crew’s massively successful ­jewelry line in 2005. She got a bit of publicity back then under her maiden name, Lisa Finkelstein, but after ­marrying in 2011 and embracing a childhood nickname, Lele Sadoughi (pronounced Lee-lee Suh-doogie) felt ready to juggle one final corporate gig at Tory Burch with the debut of her namesake collection.

To say that the Lele Sadoughi line has been a hit is an understatement. Available at select Nordstrom, Saks Fifth Avenue, and Neiman Marcus stores, the Dallas native’s oversized pieces have been picked up by 75 smaller retailers and counting. “In the past six months, we’ve been getting requests from three or four new stores a day,” Sadoughi says. “Liberty came in and bought every earring in the line. It’s definitely a moment when people are craving big, colorful, flowery jewelry, and that’s what I do.”

Seated in the sunny living room of her six-story Chelsea townhouse, which serves as both her family’s home and her brand’s headquarters, Sadoughi expresses a breezy confidence in her aesthetic. On the recent trend toward “small, delicate, demi-fine” jewelry, she says, “That’s just not what I want to wear, so I stay with things I think are really fun—and there are enough people out there who also want that. I don’t like to wear the same thing every day. I throw on jeans and a fabulous pair of earrings, and I’m set.”

As her look-alike preschool-age daughter, Ivy, plays among trays of samples, Sadoughi—wearing a gray crewneck sweater and black skirt, plus three-inch-long drop earrings from her current Rio collection—chats about her work. The intricate three-tiered design combines a crystal pavé post, a tortoiseshell acetate circle, and a blue acetate crystal-centered hibiscus flower. On her, the enormous earrings read as neutral. Images of the designer modeling her signature crystal lily, calla lily, and beaded hoop earrings while out and about in New York City drive online sales from her Instagram account.

Sadoughi offers a sophisticated product at an attractive price point ($100 to $400), a combination she perfected at J. Crew during the economic downturn. “Everyone became more sensitive to wearing things that were attainable,” she recalls. “It wasn’t [a time to say], ‘This is my diamond necklace’; it was, ‘This necklace is fun, and you can get one, too, for less than a hundred dollars.’ ” Under her leadership, J. Crew’s chunky jewelry hit $40 million in sales in its first five years. In the bargain, Sadoughi received a crash course in running a business.

“My advice to anyone just out of school is to learn on somebody else’s dime,” she says of working in a corporate setting. After earning a degree in advertising from the University of Texas, Sadoughi entered the fashion business working on trims for Rebecca Taylor, a natural launchpad to creating jewelry for brands ranging from Old Navy to Anthropologie. “I was a designer,” she says, “but I learned so much about merchandising and styling and production, helping to name products and thinking, ‘Who is [the ­customer], and how is she going to wear this?’ ”

By the time Sadoughi left a part-time post as jewelry design director at Tory Burch, she knew exactly where she wanted to position her line and how to manufacture it affordably on a large scale. “I’m not competing with $50 or $60 pieces,” she explains, “but there’s a lot of designer-­label jewelry that is $500, $600, upward to $1,200, and I thought, ‘I know how to do this and make it look nice for 30 percent of that.’ ” Sadoughi favors lightweight acetate in cheerful colors and patterns, gold-plated brass, pavé crystals, and stones such as halite and marble. For those who don’t care for flower motifs, she offers interlocking geometric shapes inspired by her love of Machine Age architecture. Each piece is packaged in a cloth pouch adorned with a tiny crown logo.

As her company has grown, Sadoughi remains its sole designer, not an onerous burden for someone accustomed to turning out new collections every month for multiple brands. Her top-selling lily and daffodil acetate earrings began with sketches edited on a computer. “I study the shape of a bloom, cut and paste the shape, shave off some of the sides, and add crystals,” she says. “They remind me of the papier-mâché earrings my mom used to wear in the ’80s.” Her factory in China fabricates a prototype of each design for her approval. “I’ve been doing this for so long, my first samples usually come back nicely, which is good, because I don’t have time to redo them,” she says with a laugh.

There’s nothing precious about the way Sadoughi describes her creations. “Some designers don’t like the term costume jewelry, but I do,” she says. “I try to keep a bit of elegance, but I think it should be crazy and big, and I’m not trying to be real in any way.” To her amusement, fans sometimes mistake Lele pieces for fine jewelry. “They’ll call and say, ‘I’ve worn this every day for years and now it’s tarnished.’ And I’m like, ‘Um, it’s costume jewelry.’ Or ‘This is my favorite piece. Can you fix the dents in it?’ No, but we’ll replace it, because this is a person who really loves it and we want her to be happy.”

The company’s product mix continues to evolve, based on Sadoughi’s instinct for what stylish women want. “When I started, [the line] was 80 percent bracelets in a million colors, stacked on each arm,” she says. “Then I did the big necklaces. For the past two seasons, my collection has been 80 percent earrings. That’s what people are buying, and I think it will continue going into holiday. After that, I’ll move on. Costume jewelry is fun because it changes so fast.”

In the six years since launching her business, Sadoughi has given birth to her son, Asher, and his little sister, Ivy (featured on Instagram with the hashtag #sadoughikids), and set up a showroom and an office on the top floor of her house. The shipping department is in the basement, accessible by an elevator outfitted with a Little Tikes chair for the family’s youngest riders. Sadoughi currently has five employees but is looking to hire a marketing director and engage a branding company. To reach a younger demographic, she recently designed a piece of jewelry for a PopSugar subscription box and a few lower-price items for the online styling service Stitch Fix.

All this activity suggests a larger ambition, which the entrepreneurial designer affirms. “In five years, I feel like Lele Sadoughi will be known as a lifestyle line,” she says. Her interests are eclectic, including a forthcoming collection of retro cloth headbands that she’s been previewing on Instagram, jeweled clutch handbags, and home accessories such as trays, napkin rings, and picture frames.

“When I started this business, my husband said, ‘You need to write this down—who is the Lele Sadoughi girl?’ ” The answer, she concluded, was someone a lot like her.

“There are people in the world who dread getting dressed, and I’m the complete opposite,” she says. “My attitude is, if you have a pink dress, you should wear it. The Lele girl has fun with fashion and enjoys putting together a look that’s unique. She’s not a wallflower.”

Top: Golden Lily necklace in 14k gold–plated brass; $650; Lele Sadoughi; 212-228-8422; lelesadoughi.com

(Sadoughi: Jason Savage)