Naomi Leff, who died Sunday at age 64, was the designer behind the Polo Ralph Lauren store in the ornate Rhinelander mansion on Madison Avenue, a novel concept in retailing that brought to commerce the feel of a stately English home.

The store was lauded both for its aesthetic value as an architectural renovation and restoration and for opening new vistas in retailing. Despite the massive total floor space, the shopper was presented with sumptuous rooms of residential scale and could experience the slightly naughty sensation of poking through intimate possessions of the wealthy.

Already a specialist in upscale retail design when the Lauren store opened in 1986, Leff went on to design the interiors of conference centers, screening rooms, vacation homes, boats, and even jets for some of America’s largest corporations and richest individuals.

Leff was never identified with a particular period style but liked to say that her background in retail design informed all her work, even the private homes. “Being a designer,” she once said, “means listening to your clients, seeing their vision, and then interpreting.”

Her close attention garnered enthusiastic loyalty from clients. For Mr. Lauren, Leff also designed a ranch in Colorado and an estate in Bedford, N.Y. Leff designed the corporate headquarters of the DreamWorks studios in California, as well as luxurious residences for its founders: Steven Spielberg, at East Hampton and Manhattan; Jeffrey Katzenberg, at Malibu and Park City, Utah, and David Geffen, at Manhattan and South Beach, Miami.

Leff designed a country home for Mike Nichols and Diane Sawyer, renovated a yacht for Barry Diller, and translated Milan fashion cool for the American mall by creating the prototype for the Armani chain of A/X shops. Other clients included Tom Cruise and Nicole Kidman, and Shearson Lehman Hutton, for whom she created interiors of two corporate Gulfstream jets based on the racy dashboard of a Maserati.

Asked in 1989 by the Guardian how much the jets cost to refurbish, Leff coyly replied, “Oh … a lot.” Price was seldom an important consideration for those who used her services, though discretion was.

Born in the Bronx, Leff attended SUNY Cortland and earned a master’s degree in sociology at the University of Wisconsin before graduating from the Pratt Institute with a master’s in environmental design. She was hired in 1973 by the design firm John Carle Warnecke Associates, where she worked on store displays for Neiman-Marcus and Bergdorf Goodman. In 1975, she became senior designer at Bloomingdale’s, where she renovated old stores and designed new ones. “I used to work with assistant buyers whose very life depended on their selling the requisite number of pencils or sweaters each day,” Leff told the Guardian. “They would call me up and say, ‘Why aren’t these things selling? Get down here right away!’ Usually it was something very simple like the light was in the wrong place but it made me very aware that I was in a partnership. I looked at the sales reports every day just as anxiously as the buyer did.”

After four years at Bloomingdale’s, Leff struck out on her own. She initially found business tough going, particularly as a woman. The retailers she met at Bloomingdale’s said: “Go out on your own; we’ll bring you business,” she said. “They did not add parenthetically, ‘After you prove yourself.'”

In 1986, Leff designed the Rhinelander store at Madison Avenue and 72nd Street for Polo Ralph Lauren, which was also an important supplier of Bloomingdale’s. Leff did exhaustive historical research on the structure, which was built in 1898 but never actually occupied by the society matron who had it built because she went broke during construction. Leff added a dominating mahogany staircase and recast ornamental plasterwork from existing fragments. Stone fireplaces, wood-paneled walls, leather chairs, and Oriental rugs provided an apt backdrop for Lauren’s wares. Everything was meant to further the illusion that the store was a private residence. A construction crew of up to 400 labored to build what was, by general consensus, among the major marketing successes of the 1980s.

From simulating a private residence, Leff went on to design the interiors of many luxurious private homes. In 1999, she told Town & Country magazine that store design helped to inspire her home designs, in part because in store design she had acquired expertise in electric and lighting systems and coordinating large groups of consultants, skills many interior design firms couldn’t muster. There was a theatricality about her designs. “Sometimes there are two kitchens,” she said. “When a family wants … the tradition of eating in the kitchen, to capture that old happy family feeling, they don’t necessarily want the private chef in there with them. So they have a second kitchen where the real work happens. The chef is making dinner in one kitchen, and they’re eating it in another.”

What clients seemed to like best about working with Leff was her indefatigable sense that the client was al ways right. “Steven Spielberg is so strong conceptually that he can walk into an empty room and give you a paragraph that paints the whole picture of what it should become,” Leff told Town & Country. “He’s a special client. But they all are.”

Said Denise Kuriger, who worked as a senior designer with Leff during the late 1990s: “She was an important female trailblazer in the industry – a great role model for other women who work in this business.”

Leff won many awards for her work, including being named to Interior Design magazine’s hall of fame, a Lumen award from the Society of Illuminating Engineers, and a Living Legend award from Pratt Institute.

She was unmarried.