The death was announced on CNN by Anderson Cooper, Ms. Vanderbilt’s youngest son, who said the cause was stomach cancer.

The railroad and shipping heiress was 10 when she became the subject of a sensational custody battle in 1934 — one that gave Depression-era America an irresistible window into the lives of the fabulously wealthy. The era’s press dubbed Ms. Vanderbilt the “poor little rich girl,” leaving her with an aura of mystery that she never escaped.

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She made appearances in gossip columns for her plethora of romantic liaisons — with Frank Sinatra, Howard Hughes and Gordon Parks, among others — and her nuptials to the conductor Leopold Stokowski and director Sidney Lumet, two of her higher-profile marriages. Her social companions included designers Bill Blass and Diane von Fürstenberg and the writer Truman Capote.

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Four husbands, four sons and more than 40 years after the court case that made her famous, she courted the spotlight by merchandising her celebrity. She turned “Gloria Vanderbilt” into a label prominently displayed on the backside of a line of form-

fitting blue jeans for women and helped launch a disco-era fashion craze.

Her jeans were ubiquitous by the 1980s and earned the onetime child millionaire a fortune of her own, as well as another backhanded sobriquet: The Duchess of Denim.

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“What’s cool about her is she very easily could have done nothing with her life, but she chose to create,” Cooper said in 2009.

Her creative drive, she often said, arose from a need to make order out of her chaotic childhood.

A stunning beauty known for her taste and style, she became a bewitching model captured by leading photographers such as Parks and Richard Avedon, and she had a short-lived drama career on stage and television in the 1950s. She also published books of poetry, memoirs and, at 85, an erotic novel.

She said the most painful moment of her life was witnessing the suicide of her 23-year-old son Carter Vanderbilt Cooper, who in 1988 leaped from the 14th-floor terrace of her Manhattan apartment. She wrote a book, “A Mother’s Story” (1996), about her efforts to cope with grief after his death.

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She was sturdier, friends insisted, than the “poor little rich girl” of dated news coverage.

“Hard knocks,” she once said, “helped me find myself.”

Gloria Laura Morgan Vanderbilt was born Feb. 20, 1924, in New York City. She was the only child of Reginald Claypoole Vanderbilt and his second wife, Gloria Morgan, a teenage socialite less than half his age.

Her father was a great-grandson of Cornelius Vanderbilt, the 19th-century tycoon and philanthropist. Her father was a gambler who squandered much of his inheritance before dying in 1925 of cirrhosis of the liver and other complications of alcoholism.

“Little Gloria,” as the toddler was called, became one of two heirs to a $5 million trust fund, the equivalent of almost $67 million today. The other was a half sister from her father’s first marriage.

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Widowed at 21, the elder Gloria Vanderbilt financed her lifestyle through trust income earmarked for her daughter’s upbringing. The allowance was generous and set the stage for Ms. Vanderbilt’s lonely childhood.

By all accounts, her mother was remarkably negligent, preferring partying in Europe to parenting. The mother and her glamorous identical twin, Thelma Furness, kept company with royalty. Furness had an affair with Edward, Prince of Wales, before introducing him to Wallis Simpson, the American divorcée he would give up the throne to wed.

Much of young Gloria’s early childhood was spent in Paris with her longtime nanny. She also stayed with her grandmother, Laura Kilpatrick Morgan.

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Laura Morgan was so disdainful of her daughter’s mothering skills that she plotted with a relative on the Vanderbilt side of the family to permanently remove the child from her daughter’s custody. Morgan and Gertrude Vanderbilt Whitney — a paternal aunt who had married into another prominent family — sought to have young Gloria live with Whitney permanently.

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At the start of the New York trial, the judge warned that “dirt” from the press coverage would make the girl forever infamous.

Lurid testimony riveted the nation during the nearly two-month trial. A nurse said Gloria’s mother was a cocktail-crazed dancer, a devotee of erotica and the mistress of a German prince. A chauffeur testified that the girl’s mother had several lovers. A French maid raised the specter of lesbianism, causing the judge to close the courtroom.

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In chambers, young Gloria renounced her mother to the judge.

When he pointed out that she had “lived a long while” with her mother, the girl responded, “Yes, but I have hardly seen her. She has never been nice to me.” After a suggestion that perhaps she could learn to love her mother, Gloria said, “No. She never even kissed me goodnight.”

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Later, Gloria said she had been coached to speak against her mother and kept repeating to herself during the trial, “When I grow up, I’ll marry and have a lot of children and I’ll love them so much that they’ll never be ­unhappy.”

The girl’s aunt was awarded primary custody, with her mother allowed limited visitation rights. Gloria’s upbringing remained strict and socially stifling and, at 17, she dropped out of school to visit her mother in Beverly Hills, Calif.

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She felt like a bird uncaged, she later said. She became engaged to the first actor she met, Van Heflin, and was squired around town by such stars as Errol Flynn and George Montgomery.

In 1941, she married agent Pat di Cicco, a gambler with a hair-trigger temper. She wrote in her 2004 memoir, “It Seemed Important at the Time,” that the marriage was “like walking on a tightrope, never knowing what would set him off on one of his violent spells when for no apparent reason he’d turn and vent his anger on his longing-to-please, docile wife.”

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The day after her divorce in 1945, she eloped with Stokowski. She was 21, and he was 63 but looked far younger. Ms. Vanderbilt and Stokowski shared a grand passion, according to his biographer, but he could be controlling and emotionally distant.

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They lived a quiet life in New York and had two sons, but halfway through their 10-year union, she had a nervous breakdown. Advised to find a creative outlet, she began to paint, write poetry and study acting.

She was 30 and working as a stage actress when she left Stokowski, encouraged by a fling with Sinatra, who “created a kind of magic,” she later said.

In a sad echo of her childhood, Ms. Vanderbilt battled Stokowski in court for custody of their sons after the couple divorced. She won but wouldn’t allow her children to testify.

Her next marriage, in 1956, was to Lumet, a rising television director who later made acclaimed films such as “Dog Day Afternoon” and “Network.” She also had a fledgling acting career on TV during those years but ultimately said she felt unfulfilled and wanted more children.

The marriage ended in 1963, and that same year, Ms. Vanderbilt married Wyatt Cooper, a dapper screenwriter who went on to edit Status magazine. She called him her “soul mate.” His sudden death in 1978, at 50 and after a heart attack, left her caring for their two young sons.

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She never married again but seldom lacked for companionship. One of her deepest attachments was to photographer and filmmaker Parks, whom she met in 1954 when he took pictures of her for Life magazine. They formed a romantic bond that spanned decades.

“It’s almost inconceivable now to imagine how surprising it was in the 1950s for us to be seen together, simply because he was black and I was white,” she recalled in her 2004 memoir. Parks died in 2006.

Survivors include two sons, Anderson Cooper and Stan Stokowski. She was estranged from another son, Christopher Stokowski, who she said decided to “cut himself off completely” from the family.

Of all her endeavors, Ms. Vanderbilt said painting was her “strongest gift.” When a 1969 exhibit of her paintings and mixed-media collages led Johnny Carson to feature them on his late-night show, the publicity helped Ms. Vanderbilt launch a design career that included home accessories, paper goods, scarves and clothing.

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Inspired by the high-end Italian jeans she wore, Ms. Vanderbilt decided to “do one cheaper but with a good fit,” she later said. Calvin Klein had just come out with a similar concept, and together they fueled a trend.

To her surprise, according to friends, she ended up earning her own Vanderbilt fortune, making $10 million from the jeans in 1980 alone. Later that decade, she left her denim empire and sold the rights to the “Gloria Vanderbilt” name.

Her wealth had begun to erode after she formed an unlikely business partnership in 1980 with her lawyer and a psychiatrist, who swindled her out of a large sum of money, according to a 1993 court ruling that awarded her about $1.5 million.

She never recovered a dime, Ms. Vanderbilt said in 2009, and ultimately had to sell her summer home in Southampton, N.Y., and downsize her Manhattan residence.

In her later years, she remained a redoubtable presence on the New York social scene and relished the capacity to make a stir. Hence her novel “Obsessions,” which the New York Times declared perhaps “the steamiest book ever written by an octogenarian.”