Jordan Mooney, better known as simply Jordan, a glowering, beehived Valkyrie in rubber and spiked heels who became an avatar of punk style when she presided over the transgressive London boutique that hatched the Sex Pistols and other provocations, died on April 3 in Seaford, East Sussex. She was 66.

Her brother, Roger Rooke, said the cause was bile duct cancer.

Ms. Mooney was just 19 in 1974 and working as a shop girl at Harrods, but she was already a presence when she walked into the store Sex, at 430 King’s Road, with a peroxide bouffant, green makeup and belted Mackintosh.

“You were like a little icon,” her new boss, Vivienne Westwood, told her years later, adding, “I’d never seen anything like you before.”

With its puffy pink vinyl sign, seditionary manifestoes, rubber and leather fetish wear and T-shirts emblazoned with fragments of text from S&M novels, among other slogans, the store was also something not seen before. It was a laboratory for its proprietors: Malcolm McLaren, an art school dropout and music impresario, and his girlfriend, Ms. Westwood, who made the clothes to her own skewed, wildly original and sometimes problematic vision — they might include swastikas, or photographs from pornographic journals.

The couple would later be known as the godparents of punk, and Ms. Westwood would earn an Order of the British Empire award for her contribution to fashion.

“Moral discomfort,” Cathy Horyn wrote in The New York Times in 1999, “was their pleasure.”

Ms. Mooney, a muscular former ballet student and track star, became the living embodiment of the store and also its gatekeeper, embracing its anarchic ethos — particularly its rubber wear — with gusto and flair. She was an imposing figure, her hair swooped up in a stiff bouffant, her eyes swathed in black like a superhero’s mask.

Commuting each day by train from her parents’ home in East Sussex, she invited outrage and often cleared entire cars, sporting outfits like a see-through ensemble with bra, underpants and fishnet stockings she had customized by burning holes in them with a cigarette.

Sometimes the conductors would move her for her safety into the first-class car, where she would find herself surrounded by businessmen pretending to read their newspapers. When the commute became too onerous, she moved to London and roomed with a dominatrix who shopped at Sex for her work gear.

“Men were confused by me,” she told The Guardian in 2019, when her memoir, “Defying Gravity: Jordan’s Story” (written with Cathi Unsworth), was published. “They would wolf-whistle, shout all kinds of things, even offer me money, because they didn’t understand why I looked like I did. I was running a gantlet every day. People were scared of me. And the funny thing is, I was actually quite shy.”

Ms. Mooney terrified many would-be shoppers, but the fetish customers, particularly the rubber wearers, found her a welcoming, sympathetic presence (even though she did not share their proclivities). A newscaster brought her bouquets of flowers because she helped outfit him in rubber underpants, and after shopping he liked to wink at her that night on television from his newsreader’s desk, knowing she could picture what he was wearing under his three-piece suits. (However, when a member of the British nobility invited her to ride around his stately home on a motorcycle in full rubber regalia, she declined.)

Sex was like a club or a salon, and when Mr. McLaren made a band out of fledgling musicians who hung out at the store, he named them the Sex Pistols to promote the place. Mr. McLaren had been inspired by the absurdist political theater of the French Situationists, and he engineered the Sex Pistols’ performances more like performance art or a Happening than a proper rock gig.

The fearsome Ms. Mooney was part of an entourage that appeared onstage with them. She did not sing, but she might add to the general chaos by hurling chairs at the audience. At one early event, when the press arrived, Mr. McLaren yelled at her: “Do something, Jords! Take your clothes off, girl.” (She removed her shirt.)

To many, she was the first Sex Pistol.

“There are people who embody a time and a place,” said Jon Savage, the British cultural critic and author of “England’s Dreaming: Anarchy, Sex Pistols, Punk Rock and Beyond” (1992). “They don’t leave a body of art or writing, but their image is such they might as well have. Jordan was that impressive. Her physical presence was that powerful.

“I saw her as an English archetype,” he continued. “Like a parody of a 1950s suburban housewife crossed with a dominatrix, the mirror image of Margaret Thatcher.”

Ms. Mooney, he said, was a figurehead for a generation of disaffected teenagers during the grim Thatcher years. She was heroic in a way, a superhuman and quite fantastic creation of her own making, an Amazon to kick to the curb the wan and waifish Twiggy types who had preceded her. Ms. Mooney said she saw herself as a walking art project and was liberated, like her punk sisters, by the idea that women could be threatening. Punk, anarchic but unisex, was a great equalizer.

Ms. Mooney also worked as a manager and stylist for the glam-punk band Adam and the Ants. She often performed with them, too, howling a song called “Lou,” a critique of Lou Reed she had written after being disappointed by one of his shows.

She was a muse to the filmmaker Derek Jarman, memorably appearing in his campy punk allegory “Jubilee” (1978), dancing on pointe in a fluffy “Swan Lake” tutu on a gritty backlot, in front of a bonfire in which the Union Jack sizzles.

Mr. Jarman filmed her wedding in 1981 to Kevin Mooney, who was for a short time the bassist in the Ants. She was 26 and Mr. Mooney was 18, and when Ms. Westwood heard the news, she fired her. (The shop, which had been renamed Seditionaries in 1976, was at that point known as World’s End.) Marriage, Ms. Westwood felt, was a burdensome bourgeois construct, and for Ms. Mooney to enter into to it was an unforgivable transgression of the store’s philosophy and Ms. Westwood’s own beliefs.

The marriage was not a happy one, marked by the couple’s heroin habits — Mr. Mooney sold her clothes at one point, and once hurled her kitten against a wall — and Ms. Mooney escaped after two years. She detoxed on her own, at her parents’ house in Seaford, telling them she had the flu. She remained in her hometown and reinvented herself as a breeder of Burmese cats, and a veterinary nurse.

In addition to her brother, Ms. Mooney is survived by her sisters, Rosalind Jean Craven and Sally Reid, and her boyfriend, Nick Linazasoro, a music journalist.

“Jordan was incredibly strong, and she always knew how to say no,” Mr. Savage said. “Unlike many of that era, she became a human being.”

Pamela Anne Rooke was born on June 23, 1955, in Seaford. Her father, Stanley James Rooke, worked as a clerk for the dental board of the National Health Service; her mother, Rosalind Winifred (Needham) Rooke, known as Linda, tended bar in pubs and worked as a seamstress and saleswoman in a haberdashery.

Pamela studied ballet and was a high school track star. When she was 15, she was hit by a car and fractured her pelvis; it took her four months to learn to walk again, and many more before she could dance.

She gave herself a new name, Jordan, for Jordan Baker, the chilly “Great Gatsby” character. She did well on her high school exams, particularly in law and English, but decided to explore London, then a city of possibility and reinvention, seeking out the kindred tribes she had found in Brighton’s nightclubs, particularly its gay clubs, where the transformative potential of costume seemed limitless.

“It was like seeing a unicorn on the King’s Road,” Michael Costiff, a designer and party host, told her, recalling the first time he saw her. “And then, just like Greta Garbo, at the height of your powers you disappeared.”