But she also had a positively girly crush on fashion, like the clothes her great-grandmother wore.
"She was always dressed to the nines," Stephenson said. "Her husband was a farmer, but she really made it happen."
Stephenson said much of her family loved fashion and exposed her to styles both bohemian and elegant. The fashion bug bit her in elementary school, when she was determined, like Brooke Shields, to let nothing come between her and a pair of Calvins.
Stephenson said a farm girl's back-to-school shopping usually meant two new pairs of jeans and a new sweater. But she begged her mother to buy her just the one pair of designer jeans that year, and she loved them so much she wore them almost every day.
Since it was a pair of jeans that first captured her heart, it's only fitting that Stephenson is venturing out by putting her name on a women's denim collection. A men's collection will follow next spring.
Stephenson has distilled her love of high fashion, her tomboy upbringing and her enchantment with things that are humble and durable into her new line of denim, which will go on sale this summer under the Stephenson label.
These days, Stephenson travels between her studios in New York and Los Angeles, but anyone who meets her hears about Johnston County before too long. In her first collection, she has named her five-pocket style Johnston, and it's available in a Swift Creek rinse. Her jeans come in a Reedy Branch shape too, and Stephenson said she would add boot-cut "894" and "934! styles in her next collection.
Stephenson said her Johnston heritage distinguished her designs in the white-hot market for premium denim. "I think it's so important to come back here and see what inspires me," she said. "You have to offer a different product because there are so many on the market."
Other Johnston-inspired touches might be less obvious to the casual eye - supple leather buttons and copper stitching the color of clay, the pinecone logo and denim as sturdy as a farmer's dungarees. She even answers "Johnston County" when fashion writers ask her what her jeans look like.
"They say, "I don't know where Johnston County is, but it must be a beautiful place,"" she said.
Stephenson, tall and lean enough to be a denim model herself, said she was fairly comfortable working in an Atlanta advertising job. But then, the "you only live once" alarm went off in her head. At 28, she moved to New York and earned a degree from the Parsons design school. After graduation, she climbed the ranks at Garfield & Marks, a sportswear maker that sells through Nordstrom and other department stores, to become head of denim and casual pants.
"I touched on every aspect of the business, and that gave me confidence," she said.
Five years later, Stephenson decided it was time to take another risk. She wrote a business plan in 2005, braced herself to do without her six-figure salary and started the Stephenson Denim Finery. "I've never been so poor or so happy in my whole life," she said.
Stephenson said she parlayed her Southern sweetness and polite persistence into deals with exclusive denim vendors in Italy and Japan who typically refuse upstarts. She said her dream was to bring her product back to the North Carolina economy, by either reviving some of Harnett County's old denim mills or working with a premium denim-maker in the state.
For Stephenson, scrimping on materials, fit or details will never be an option. She prefers well-made, classic pieces that earn their high price over items that make themselves disposable by fading, pilling or losing their shape.
And in her mind, the simplicity of humble, hard-working, versatile denim is as stunning as the people and ideology of the place she calls home.
Stephenson said she had been pleased to see her jeans pass an early wear-ability test. She said it's common for shop owners considering the line to toss a pair to whatever salesperson is working to see them in action. Invariably, even if the size or style wasn't perfect for the body modeling them, the models have gushed about them, Stephenson said.
"Our jeans seem to fit everyone well," she said.
Big success could be just around the corner for the girl from McGee's, but she said it's just as important to her to stay true to her business ideals.
"I am bringing a sustainable product," Stephenson said. "I want to be nice to people, be a nice boss, pay people on time, and not say I can do things I can't deliver."
Stephenson said her family splits its time between the beach and the McGee's farm where she grew up. And during a family beach trip last week, she lined up a Wrightsville Beach boutique called Oliver to be the only North Carolina retailer of her collection, which will retail from $190 to $250.
Also, her jeans will be available through shopbop.com and activeendeavors.com, as well as a handful of upscale boutiques in several major cities. In New York, luxury department store Bergdorf Goodman will stock Stephenson's jeans.
And even before the first stack of jeans has made it onto a shelf, Anthropologie has already recruited Stephenson to do an exclusive, lower-priced collection called Enson. Stephenson said the Enson collection would boast the same styles and fit, just in a slightly less regal quality of denim.