Gloria Vanderbilt first ventured into the fashion world as a model. She was photographed by top names including Richard Avedon and Horst P Horst and appeared in Vogue as well as Harper’s Bazaar. It wasn’t until the 1970s, when Vanderbilt was in her 50s, that she established her design credentials, becoming an early pioneer of stretch jeans.

Vanderbilt worked with manufacturer Mohan Murjani to popularise jeans for women at a time when they were largely designed for men. She was among the first to use a famous family name in the marketing of a fashion line, emblazoning her signature across the back pocket of the famously fitted designs. The Amanda jeans which – as she put it – “really hug your derrière” cemented her place in fashion history, and proved innovative enough to spark a $100m (£79m) empire.

“The marketing of Gloria Vanderbilt jeans is one of the most dramatic American business success stories of the decade,” reported the New York Times in 1979. Yet her style legacy goes beyond the clothes she designed: as an heiress and socialite, Vanderbilt regularly featured in best-dressed lists. She expanded her product line to include other logoed items, as well as perfumes, sheets, shoes and accessories. Meanwhile, her friend Truman Capote is said to have based the character of Holly Golightly from Breakfast at Tiffany’s on her. The novella was famously made into a film starring another fashion icon, Audrey Hepburn.

Vanderbilt was admired by others within the industry, with fellow designer Roy Halston Frowick, AKA Halston, remarking that she had “become a professional in the most difficult, cutthroat business there is, and I say, ‘good show’.” Designer Diane von Fürstenberg, best known for popularising the wrap dress, also noted that Vanderbilt “tried to do many, many things for many, many years. The thing that you least associated her with – jeans – worked.”

Gloria Vanderbilt, Vogue 1968. Photograph: Gianni Penati/Getty

Like Lee Radziwill, who also died earlier this year, Vanderbilt might also be described as “the original influencer”, often appearing in person to promote the products bearing her name. From 1978 to 1984, she was reported to have earned more than $17m. However, by the time the Gloria Vanderbilt Apparel Corporation was sold to the Jones Apparel Group in 2002 for $100m, she had withdrawn all interest in the company.

“I’m not knocking inherited money,” she told the New York Times in 1985, “but the money I’ve made has a reality to me that inherited money doesn’t have.”

In a world where the denim industry has become king and worth an estimated £71bn, Vanderbilt’s passing will rightfully reflect on – and celebrate – the legacy she leaves behind.