Sister Parish, the grande dame of American interior decorating, was a young Depression-era mother when she embarked on her career. She had no formal training in design, and yet she went on to reimagine the rooms of the White House with Jacqueline Kennedy after her husband became president.

Mrs. Parish exalted luxury, yet the interiors she and her business partner Albert Hadley created for the homes of Brooke Astor, Bunny Mellon and Oscar de la Renta had a comfortable, lived-in feel. Rooted in traditional American decorative arts, she was the first to mix and match furnishings from different eras, styles and price points.

A fan of chintz and ticking stripes, she treasured collections and used vibrant colors in her decorative schemes; she painted floors, layered textiles and put great emphasis in selecting furniture that would give a house a sense of permanence. She worked well into her 80s and died in 1994.

These days, Mrs. Parish’s family is devoted to bringing her aesthetic sensibilities to a wider audience. Her great-granddaughter, Eliza Harris, 32, is creative director of Sister Parish Design, a line that her mother, Susan Bartlett Crater, introduced nearly 20 years ago and which focuses on recreated fabric and wallpaper patterns from the archives of Mrs. Parish and Mr. Hadley. (Ms. Crater’s mother is Apple Bartlett, Sister Parish’s now 88-year-old daughter.)

As part of this effort, Sister Parish Design is hosting its first retail pop-up at Montage Antiques in Millerton, N.Y. until Nov. 28. The pop-up is tented in the holiday version of the Parish Dolly fabric, a rose pattern that was in Caroline Kennedy’s bedroom at the White House.

Against a backdrop of Sister Parish memorabilia, the pop-up has a festive flair. Mrs. Parish loved Christmas and had specific traditions: Presents were wrapped in crisp white shelf paper with bright red ribbon, and Rigaud Cypres candles were paired with bouquets of paperwhites, said Ms. Harris.

In addition to holiday accents, the line includes dishware, linens and quilts in a variety of patterns. Antiques collected by Mrs. Parish and the other women in her family are also available for sale, along with collages highlighting birds, butterflies and wildlife made by Ms. Harris’s grandmother, Apple Bartlett.

Since its inception, Sister Parish Design products have been offered exclusively to designers through the trade. But after Covid-19 hit, Ms. Crater, the company president, and Ms. Harris, who has been with the company since 2018 — she was previously an interior designer with the Manhattan firm Markham Roberts — re-evaluated their business model.

“A year-and-a-half ago, we watched showrooms closing, and the design industry changed very quickly,” Ms. Harris said. “We didn’t see a reason to lock out the retail customer anymore.” The company’s entire product line, including its signature fabrics and wallcoverings, is now available online, direct to the consumer. Each new pattern introduced is based on one in Mrs. Parish’s archives.

Interior designers continue to comprise the bulk of Ms. Harris’s clientele, but she is excited about reaching homeowners directly. “Not everyone has access to an interior designer,” she said. “Some design enthusiasts just want to wallpaper a room, and we want to be able to support them.”

Providing customer service, she added, is different when dealing with an interior designer, who typically looks to the brand to provide specs and samples. “The consumer wants more of an education,” Ms. Harris said. “They want beautiful lifestyle imagery and more suggestions on how to use our products.” Last year the company introduced a video series, “Tell a Sister” that serves as a round table in which Ms. Harris interviews female design-minded professionals.

“My great-grandmother laid the groundwork for women leadership in the business of design, and we want to carry that on,” she said.

Sister Parish Design is also collaborating with other brands, including teaming up with Artemis Design Company, a workshop in Boston that makes shoes out of Kilim textiles. In January, the company will collaborate with Tibetano on a collection of handwoven flat weave and rag rugs based on some of its most coveted patterns.

“The rugs are not only luxurious, they are also very practical,” Ms. Harris said. “Sister Parish believed in lasting craftsmanship and design that showed the ‘work of the hand.’ The rugs are a beautiful illustration of both.”

The company is also committed to supporting local artisans and vendors. “All of our products were made in New York during Covid,” Ms. Harris sad. “Since the home industry was blowing up, we worked with a fashion workroom in the city because fashion was so quiet at the time. They did a great job.”

Ms. Harris, who is down-to-earth and endearingly enthusiastic about her great-grandmother’s legacy, will stop by intermittently through the duration of the pop-up at Montage Antiques, one of her favorite haunts. While her great-grandmother served a largely elite clientele, Ms. Harris has a slew of cost-saving design tips at the ready for the next wave of design enthusiasts.

“You can absolutely create great design on a budget,” Ms. Harris said. “If you buy one dart of our fabric, you can make a headboard that can be passed down to another generation.” She recalls a linen velvet sofa Mrs. Parish had made for her parents when they got married nearly 40 years ago.

“My parents still have the sofa,” she said. “It’s still beautiful.”