Monika Tilley, Fashion Designer and Activewear Pioneer, Dies at 86

Monika Tilley, a designer of racy swimsuits that glistened from the covers of Sports Illustrated magazine on models like Christie Brinkley and Cheryl Tiegs and a pioneer of activewear and loungewear, died on Dec. 23 in Manhattan. She was 86.

Her daughter, Mona Tilley, announced the death in January. She said her mother died in a hospital after having multiple strokes.

Ms. Tilley was not a name designer like Bill Blass or Calvin Klein; she was an industry talent known for her work for Anne Cole, Anne Klein, White Stag and other companies, designing what would become a uniquely American style of dressing. She created a line for Caitlyn Jenner when she was a track star in the 1970s, and collaborated with Ms. Brinkley on a line of swimwear in 1984. For the Winter Olympic Games in 1980 and 1984, she designed the parade uniforms for the American teams.

With an athletic build — she was an expert skier — and a deep, gravelly voice, the Austrian-born Ms. Tilley was an imposing and handsome figure. “But she had a sparkle; you never knew if she was making a little fun,” said Jule Campbell, the longtime editor of Sports Illustrated’s swimwear issues, who put many of Ms. Tilley’s suits on her covers. “Her swimwear designs were provocative for their time.”

Along with Norma Kamali, who designed the red one-piece made memorable by Farrah Fawcett, Ms. Tilley was emblematic of the “sexification of swimwear in the 1970s,” said Eric Wilson, a veteran fashion reporter.

Ms. Tilley and Ms. Kamali “combined a sense of athleticism with an open embrace of sex appeal in a way that would influence mainstream swimwear styles far more than Rudi Gernreich did a decade earlier, when he shocked the fashion world with the breast-revealing monokini,” Mr. Wilson said. “That was just a blip of immodesty compared to the impact of Monika’s fishnet swimsuits — that left little to the imagination about a woman’s anatomy — on loosening consumer tastes and making the stuff of schoolboy fantasies and dorm-room posters for decades.”

The nipple-baring white mesh swimsuit Mr. Wilson referred to, worn by Ms. Tiegs in the 1978 issue, was perhaps the most famous Sports Illustrated swimsuit image of all time, said Terry McDonell, editor of Sports Illustrated from 2002 to 2012. “Every swimsuit issue drew threats of cancellation and howls of objection — first from moralists and then from feminists — and this image was supercharged in that sense,” Mr. McDonell said.

It is now in the permanent collection of the Costume Institute at the Metropolitan Museum of Art.

Ms. Tilley often added saucy touches to her bathing suits, like the bits of lace on another white one-piece suit that Ms. Tiegs wore for a Sports Illustrated cover in 1983, made mostly see-through by a dunking in the waterfall behind her.

“She was Viennese, after all,” said the British designer Patricia Underwood, a longtime friend of Ms. Tilley’s. “In Austria they are very good at fur coats, loden and lingerie.”

Monika Theresia Nowotny was born on July 25, 1934, in Vienna. Her father, Franz Nowotny, worked in the department of agriculture; her mother, Margarete (Kinateder) Nowotny, taught English and physical education.

Monika earned a master’s degree from the Vienna Academy of Fine arts, an education her father allowed her to pursue only if he could check in with her teachers on a daily basis. (He did not believe art was a viable career path.)

She and Merten Arthur Tilley, an American she met when he was studying business in Vienna, married at the Hofburg Palais there in 1957, after which they settled in Forest Hills, Queens.

At first Ms. Tilley worked as an illustrator at Harper’s Bazaar. She was soon hired as a designer of children’s wear at Anne Cole. She would go on to design swimwear, sportswear and loungewear at Anne Klein and other companies.

Interviewed by The New York Times in 1964, Ms. Tilley, at the time a 29-year-old skiwear designer for White Stag, was asked to predict which looks at Innsbruck, Austria, where the Olympic Games were held that year, would become trends. She was bullish on pompom hats and stretch pants.

In 1976, The Times noted: “Designing sportswear is Miss Tilley’s life work, and she participates in many of the sports for which she designs clothes. The tennis boom has provoked a lot of crimes in the name of fashion, and her aim is to return the basic elegance to the game, using modern fabrics.”

Ms. Tilley was also, as the designer Stan Herman said, “a force in loungewear,” a category newly minted in the 1970s for women who wanted to look sharp at work but feel comfortable when they got home. It marked the end of the housedress era, as Mr. Herman, also a force in that genre, pointed out.

“Liz Claiborne was going to dress the new woman at work, and we were going to dress her at home,” he said. “Monika did a very sporty kind of loungewear: lots of notched collars and housecoats that looked like men’s shirts.”

In the late 1980s, Ms. Tilley’s signature line of loungewear for Vassarette featured ankle-length sweaters in bold stripes worn over monochromatic tops and leggings, styles that would not be out of place today.

Mr. Herman recalled that Ms. Tilley was once memorialized in a window at Lord & Taylor, in a scene featuring a Monika Tilley mannequin — her own doppelgänger — sketching at a desk and looking very official.

In addition to her daughter, Ms. Tilley is survived by her son, Martin, and her brother, Thomas Nowotny. Her marriage to Mr. Tilley ended in divorce.

Ms. Tilley was a longtime board member of the Council of Fashion Designers of America, the trade organization started in 1962 to promote American fashion. She founded the CFDA Scholarship Program in 1996 and remained closely involved in its development.

“She was an unsung hero” in the organization, said Lisa Smilor, the council’s executive vice president. “The multitude of design students that the CFDA has awarded scholarships to may not know her name or legacy. Nevertheless, she had a positive impact on their futures.”