Rankin was not formally trained in fashion design, but he brought his inventive ideas to American sportswear through his retail experience. While managing the Merchant of Venice, a SoHo boutique, he recruited struggling artists to create t-shirts and designed sporty and fashionable sweatshirt dresses that caught the attention of the fashion industry trade paper Women’s Wear Daily. Rankin continued designing for the shop, garnering more press for his stylish dresses and separates made from T-shirts and sweatshirts, as well as an order from Macy’s department store. Rankin found his niche in designing sexy, body-conscious clothes in stretch fabrics. These flexible and affordable pieces tapped into cultural trends for active and casual, yet fashionable, lifestyles. From the late 1970s, he was at the forefront of an all-American sportswear style. His work influenced other designers, as well as women’s hip hop, streetwear, and athleisure fashions, which have become ubiquitous in the twenty-first century. Vogue described him as a “cult designer” in 1989 and noted, “when Isaia first hit town, his sleek, snug cotton Lycra tube skirts, high-waisted leggings, and low-cut tank dresses were scandalously innovative; three years later, they’re staples certain women can’t get dressed without.” Isaia, as Rankin was known, was not the only American designer creating this look, however, his high-quality stretch knits were known to “hold their incredible shape on the hanger,” and although other manufacturers consistently copied his work, “true Isaia addicts will accept no substitutes.” [4]

Vogue conducted a special report in the fall of 1987 analysing the most important designers in American fashion and the future direction of the industry. The report emphasized the diversity of the emerging generation of American designers, yet Rankin was the only Black designer profiled (Willi Smith had died that spring and President Laurie Mallet represented the company in the article). Rankin was not only a rare Black fashion designer in 1980s New York, his position as an entrepreneur and Black business owner was truly remarkable. He consciously grew his business slowly, funding the entire operation himself. He bought leftover fabrics from manufacturers and progressed from selling his designs on the sidewalks of St. Mark’s Place to opening a boutique, before founding Isaia NYC in 1986. This marked Rankin’s move from a downtown “underground” designer to a member of the established fashion industry on Seventh Avenue in New York’s garment district. His business was vertically integrated with his showroom, offices, and production facilities, all located at 240 West 38th Street. His company not only created visibility for himself as a Black designer, he also employed other BIPOC and female business professionals, including Phyllis Swan, his childhood friend and the company’s CEO, and the vice-president and general manager Noelle Nieva. This venture was Rankin’s fourth label, and within two years Isaia designs regularly appeared in fashion magazines and sold at department and specialty stores across the United States, as well as Browns in London and Seibu in Tokyo. The New York boutique Charivari was an early buyer and its vice-president explained Isaia’s appeal and consistent sell through: the collections were “original and quintessentially American…In a current market glutted with cotton and Lycra his clothes stand out for their individuality and sophistication. They are always perky, sexy, and chic.” The American buyer for the Seibu Department store called Rankin, “the most creative contemporary designer in New York” and his clothes “very exciting for Tokyo.” [5]

Rankin described his design philosophy as “sleek, modern, [and] sensual,” [6] and it was evolutionary rather than focusing on dramatic change each season. Stores reordered the staples of his brand, including his twenty-inch “sex skirt” in black, season after season and reported brisk sales. Building on his core of “stripped-down and uncontrived” pieces, [7] he introduced new silhouettes and colors, as well as new stretch fabrics such as cashmere and wool, to subsequent collections. Rankin drew on his retail experience and prioritized his customers’ needs. He was known to pose as “Malcolm,” his own fictional assistant, in stores that sold his clothes to seek direct feedback on his designs. Although he described his customer as an “MTV girl,” [8] his clothes sold to a wide range of customers of different ages and income levels. 

Isaia Rankin died at the age of 35 from respiratory failure due to complications from AIDS. Isaia NYC carried on for about two years under Isaia’s mentee Megan Curran and then Michael McCollom, but ultimately could not sustain itself without Rankin. American fashion tends to have a short memory for past designers, but Isaia’s influence is abundantly evident in contemporary fashion, from designer sweatshirts, to layered separates that play with volume, and functional, yet sexy, knit dresses and leggings. Furthermore, his position as a Black designer and businessman is important to emphasize in an industry that too often overlooks designers of colour.