Marla Aaron always envied her friends who went to art school, but doing so herself had never occurred to her. Growing up in Bedford, N.Y., she was a good student with an eye for style and a creative streak. She made jewelry for friends out of fish hooks and parts from the pieces that her grandmother had cast off, but her tinkering was more of a way to fidget than a calling.

A trip to Argentina as a foreign-exchange student, and her resulting fluency in Spanish, would end up shaping her career for the next two decades. Her first job was selling advertising spots for the Spanish Broadcasting System, a Spanish-language radio network. Later in her 20s, she moved to Madrid, where she worked in sales for Spanish Cosmopolitan and Elle magazines.

She returned to New York and spent a year at Columbia University’s journalism grad school, but after that she was more or less back where she’d started, working a series of jobs on the media industry’s business side. “It was all pretty boring,” she says. Her situation went from uninspiring to worse in her mid-30s, when as a newly divorced single mother of a young son she was fired from her job as the marketing director of Departures magazine. “That was a very hard time,” she says.

Days were given over to the job hunt, and she took to knitting and even soldering at night. An image had come to her that she couldn’t stop thinking about: a pendant based on the shape of a carabiner, the heavy-duty clips popular with climbers. She wasn’t particularly outdoorsy, but she was obsessed with the item’s sleek, architectural silhouette. She wanted to make versions out of gold, silver and platinum.

Ms. Aaron, in her New York City showroom office, says it was only after she gave the new venture all of her time that the needle began to move forward.

Ms. Aaron, in her New York City showroom office, says it was only after she gave the new venture all of her time that the needle began to move forward.

Photo: Dorothy Hong for The Wall Street Journal

She found a new job, as the head of public relations for the Interactive Advertising Bureau, a trade organization, and spent her lunch hours trawling the shops in Manhattan’s diamond district, chatting up vendors and showing them the carabiner clip she wanted to reinterpret as jewelry. “People tried and said, ‘No, that’s too much work,’ ” she recalls. “I had an idea of a level of quality and a level of excellence that was far beyond the organic, rough-hewn pieces I was making, what I call ‘art festival jewelry.’ ”

At last, she found one man who understood her vision. He surprised her and went to a hardware store to research carabiners and made a few prototypes. The pair made an agreement to begin making them together, and Ms. Aaron gave the early samples to friends and family as gifts.

It wasn’t until her final job in advertising, as senior vice president of communications at MRM, a digital marketing division of the advertising firm McCann Worldgroup, that she started to think seriously about turning her carabiner fixation into more than a passion project. It was 2012, and she was newly remarried and the stepmother of a boy around her son’s age, and had to go on a 10-day business trip to Cannes, France. She was preparing breakfast in her rental apartment when the coffee pot exploded, and the hot coffee gave her second- and third-degree burns on the length of her arm. “At the same time, my kids were leaving for summer camp, and I wasn’t going to get to say goodbye to them,” she says. “It was a snowball moment, as a parent and as a human. I turned to a very close colleague and I said, ‘I’m going home, and I’m making jewelry, and I’m sending my kids off to camp.’ ”

On the flight home, she prepared a PowerPoint presentation for her husband, who works in finance, making the case for their going from a two-income to a one-income household. “I said I was going to be around to help the family a lot more, and within six months my jewelry is going to be sold at the top 25 retail stores in America,” she says. “Everything was a big lie but I didn’t know that.”

With her husband’s signoff, she started Marla Aaron Jewelry at her kitchen table. “I was a crazed lunatic,” she says. “I was very scrappy, and I did a lot myself.” She purchased QuickBooks accounting software, and put an ad on Craigslist for a web designer. “I didn’t say I was looking for somebody who can build a site,” she says. “I said I wanted somebody who can teach me about building a website.” For the first year, she brought in income working as a freelance marketing consultant to other businesses.

Marla Aaron Jewelry sells playful designs that are often customized with personalized engravings or other bespoke details.

Marla Aaron Jewelry sells playful designs that are often customized with personalized engravings or other bespoke details.

Photo: Dorothy Hong for The Wall Street Journal

Selling jewelry was a new skill, and going door to door to shops proved challenging. In 2013, she turned to her husband and told him that she needed to stop taking consulting gigs. If her business was going to work, she had to focus full-time on making jewelry. “That’s when I put the pedal to the metal,” she says.

She begged her sons, teenagers at this point, to teach her how to use Instagram. “I had been the one who was so quick to take their phones away; it was always my go-to punishment,” she says. “Now I was like, ‘Fine, no more taking it away.’ ”

Ms. Aaron’s storytelling and advertising skills came in handy. Her Instagram voice is funny and chatty: She’ll post about everything from her husband’s beekeeping obsession to the back stories behind her latest designs—and people were quick to engage. “It was kind of off to the races,” she says. Since then, sales have doubled each year over the previous, even during the pandemic. “I have been insanely lucky,” she says.

Her business now operates out of a candy-colored, whimsically decorated showroom on West 47th Street, with 16 full-time employees and a steady stream of clients showing up for private appointments. The company, which doesn’t pay celebrities to wear its pieces, has fans in actresses Blake Lively, Julianne Moore and Cynthia Erivo. When The Wall Street Journal came by for an interview, a chef from the trendy downtown Manhattan restaurant King was selecting a baby lock pendant to purchase.

Chunky locks in many shapes, sizes and treatments are one of the design themes in Ms. Aaron’s works.

Chunky locks in many shapes, sizes and treatments are one of the design themes in Ms. Aaron’s works.

Photo: Dorothy Hong for The Wall Street Journal

Ms. Aaron’s locks—ranging from $110 up to $75,000, with some featuring precious stones—are her bread and butter. They have fanned out to include an assortment of sizes, shapes and treatments; she and her head designer are always bringing out new designs. Her playful aesthetic comes through in the chunky lockets, charms and bespoke pieces that clients commission from around the world. She recently made a bracelet for a woman in Singapore that she will give to her 7-year-old daughter on her 18th birthday. The outside of the piece is engraved with chubby hearts, kitty cats, origami and other images of the daughter’s current passions, and inside is a quote from Antoine de Saint-Exupéry’s “The Little Prince.” A client in Kuwait asked her to create a bracelet with a hand-engraved eagle, owl, tiger and fox, animals that represent members of the family, with Arabic engravings of each child’s first initial.

“The only thing I miss about my old life is that it was very easy. I was able to clock out and have a weekend,” Ms. Aaron says. “I didn’t picture myself sitting at my kitchen table for the next 50 years, but I certainly didn’t expect it to become as big as it became. It’s so much more than I expected.”

The Career Journey

Name: Marla Aaron

Age: 54

Location: New York City

Education: Bachelor of Science, communications, Syracuse University’s Newhouse School of Public Communications; Master of Science, journalism, Columbia University Graduate School of Journalism

Former Job: Senior vice president of communications, MRM, a unit of McCann Worldgroup advertising

Current Job: Founder and designer, Marla Aaron Jewelry

Aha moment: On an international work trip, a coffeepot in her rental apartment exploded, and the hot coffee burned her arm. “It was a snowball moment,” she says. “I turned to a very close colleague and I said, ‘I’m going home and I’m making jewelry.’ ”

Advice to people looking to change careers: Don’t half-step. If you can afford to devote your full attention to your new enterprise, it’s a risk worth taking. “I spent the first year consulting and trying to build a business,” Ms. Aaron says. “I did not move the needle forward on my business, and I was probably a very mediocre consultant because my mind was elsewhere.”

Write to Lauren Mechling at lauren.mechling@wsj.com