A woman who catches sight of a soldier in the battlefield with live hand grenades strung around his neck, and immediately imagines a pair of Cartier jewelry clips in their place, must be one with an attuned but very unusual eye for fashion. Lee Miller, the high-fashion model turned seminal war photographer, was just that kind of woman. But she was so much more than those two central roles suggest: she was also a writer, gardener, surrealist artist, Cordon Bleu cook and mother.

“She was the nearest thing I knew to a mid-20th-century Renaissance woman,” wrote her close friend and colleague David Scherman, the American photojournalist and editor who worked with Miller in 1940s Europe as they followed the Allies across the shattered continent in the final stages of World War II. It was Scherman who created the now-iconic image of Miller, a beautiful, naked American woman washing herself in Hitler’s bathtub, after the pair stumbled into the dictator’s abandoned Munich apartment, only hours before he committed suicide with his girlfriend, Eva Braun, in Berlin. For some, this powerful and controversial image represented not just the triumph of life over death, but also the triumph of a woman in a male-dominated world. But when Miller was asked about it, she always said that she was merely trying to wash away the stench of Dachau, the concentration camp whose liberation she and Scherman had just witnessed. But throughout her life, she was never quite able to wash away the horrors of what she had seen.

There wasn’t much Miller didn’t see in her lifetime, nor many famous people she didn’t meet. The British novelist Blake Morrison, who has written about her, believes that if you were to pitch her eventful life as a television drama it would be rejected as “too implausible a storyline”. But real life so often is stranger than fiction and, as new details continue to emerge, it is clear that Miller’s life was both strange and complicated.

Her early career as a model began, like many of her definitive experiences, with an accident. Aged 19, she was pulled away from the path of an oncoming car on a New York street, which seconds later might have knocked her down, by the magazine magnate Condé Nast – who, noticing her beauty, style and new Parisian outfit, immediately employed her as a model. What Miller learned during those days was to prove invaluable once she had moved to the other side of the lens.

This year, 70 years after the liberation of Europe, the girl in Hitler’s bathtub is being celebrated in two major exhibitions that emphasize her many talents and the ease with which she moved behind and in front of the camera. Are her beauty and innate style, as well as her own self-disparagement, the reasons why recognition for her photographic work has come so slowly? The answer is not straightforward, but its roots undoubtedly lie in her taking on a job – war photography – that was, at the time, very much a man’s world.

The first show, at the Albertina Museum in Vienna, has a neat historical symmetry to it, honoring both her position as the only woman combat officer to follow the Allied advance across Western Europe in World War II and her work in Salzburg and Vienna in 1945. Significantly, it will be the first time her images have been shown in Austria. The show’s curator, Walter Moser, finds her war photography unique partly because of her background in fashion. “Even when she photographed bombed buildings, Lee was staging fashion shows,” says Moser. “The contrast between ruined buildings and models wearing beautiful clothes is very striking.” The second show, A Woman’s War at London’s Imperial War Museum later in the year, will examine how Miller viewed gender in her work. “Nobody was ever going to give her a gun, so the camera was her weapon,” her son Antony Penrose tells me when we meet to talk about his mother.

Miller was preternaturally able to see artistic possibilities in everything and, by the time she arrived in Europe, she had had plenty of experience photographing the London Blitz. The bomb blasts, which scattered cherubs’ wings and stone roses from a church hundreds of yards down the street were, for an incipient surrealist, liberating.

But what formed this extraordinary woman, who was born Elizabeth Miller in 1907 in Poughkeepsie, New York, the second child of Florence and Theodore Miller (the latter an engineer and keen amateur photographer with a predilection for photographing his own daughter naked, well into her twenties), who ended her days as Lady Penrose, the Cordon Bleu cook, in the heart of the English countryside? The answer lies in her childhood, which was brutally cut short when, aged seven, she was raped by a family friend. She was left with unimaginable memories as well as gonorrhea, which required excruciatingly painful (and secret) treatment. Her brother John commented later that, unsurprisingly, the trauma changed her life and that she “went wild” as a result. Her parents took her to a psychiatrist, who advised her to separate love from sex, which to an extent she succeeded in doing, much to the bafflement of her many lovers. Conversely, and although deeply disturbing to modern sensibilities, the naked photography sessions with her father seem not to have worried Lee, who always adored him. By having his daughter pose naked, her father was not only her first photography teacher but may also have helped her feel comfortable about her body, giving her a sense of freedom as a model and perhaps as a human being.

The rape and its effect on her partly explain why she left home at 18, traveling to Paris before ending up in New York City, where she studied art and worked as a lingerie model to earn extra money. Within weeks, that accidental meeting with Condé Nast resulted in her appearing on the March 1927 cover of Vogue. Wearing a cloche hat over cropped hair, she epitomized Parisian chic, determination and insouciance all at once. It was a captivating look that the well-known photographers in the city, most notably Edward Steichen, the celebrated artist who turned fashion photography into an art, were desperate to capture. Cecil Beaton described her as a “sun-kissed goat boy from the Appian Way”.

With great insight into her own turbulent nature, Miller told an interviewer years later that during those New York years, when she wore fabulous couture gowns against dramatically glamorous backdrops, “I looked like an angel, but I was a fiend inside.” When a Steichen image of her in a flowing gown and pearls was used without her consent to advertise Kotex, a new type of sanitary protection, she decamped for Paris, horrified, ditching her given name en route.

Miller often described the moment she met the great surrealist photographer Man Ray as the turning point in her life. The pair moved in overlapping aristocratic circles which included the Comtesse Greffulhe, one of Proust’s models, and avant-garde luminaries such as Jean Cocteau, Elsa Schiaparelli, the dancer Serge Lifar and the illustrator Christian Bérard. According to one version, she knocked on the door of Man Ray’s famous studio in Montparnasse and told him she was his new student. “He said he didn’t take students, and anyway, he was leaving for his holiday. I said, ‘I know. I’m going with you.’ And I did.” The incongruous-looking couple – he was short and muscular and 16 years older; she was slim and nubile – lived together for nearly three years.

Man Ray taught Miller all he knew about photography and she, eventually becoming his assistant, muse, lover and model, taught him a few things about life. It was probably Miller who accidentally discovered the technique known as solarisation – later made famous by Man Ray – whereby a bold line appears around the edge of an image, when she unintentionally allowed light in while a negative was developing.

When her funds ran low, she returned to modeling, mostly sitting for George Hoyningen-Huene, the aristocratic chief photographer at French Vogue. She tried her hand at acting, most memorably as a marble muse in Jean Cocteau’s film The Blood of a Poet. But, ever the restless soul, she upped sticks in 1932 and abandoned a devastated Man Ray, returning to work in America, where she was greeted with the fanfare of a celebrity, which she now was. She began appearing once again in Vogue and in one shoot, her beguiling natural beauty showcased in a ravishing, sequined Lanvin dress, earned the caption, “Smartest worn, as Miss Lee Miller wears it in the photograph, without a single ornament.” But while she appreciated the veneer of good publicity, she found modeling clothes too passive a role and famously declared that she would rather take a photograph than be in one.

After two years in New York, running her own increasingly successful photographic studio, she impulsively gave it all up for marriage to a wealthy Egyptian, Aziz Eloui Bey (also 16 years her senior). The pair had met through Hoyningen-Huene in St Moritz, while Bey was still married. As the romance gathered pace, Miller saw the new relationship as an opportunity to get out from under Man Ray’s shadow and to live a less frenetic existence, adopting the slow pace of life in colonial Egypt. Bey understood his new wife’s “troubled soul” and wrote to her parents, promising he would “bring peace to her heart”. But taking pictures of pyramids did not satisfy what Miller called her “jitters”. By 1937 she was back in Paris, moving with her old crowd of surrealist friends as well as meeting new ones, including the English artist and collector Roland Penrose. Penrose and Miller fell in love and spent an idyllic first summer together in France in the company of Picasso, who painted six portraits of Miller. In one of them, Portrait de Lee Miller à L’Arlésienne – a reference to women from Arles, famed as femmes fatales – Picasso gave her brilliant colors for her torso, breasts and face, green lips and a mustard-yellow complexion, said to be a reference to her warm personality.

Miller and Penrose, along with a group of surrealist painters and poets including Paul and Nusch Éluard, Max Ernst and Leonora Carrington, continued on to England where, according to observers, the slightest encounter became an orgy. But although there was much nudity, there was also a desire for the women to dress with panache. Miller always liked to be considered what she called “a snappy dresser”.

“Our concern with appearance was not a result of pandering to masculine demands, but rather a common attitude to life,” said Eileen Agar, the British surrealist painter who was part of Miller and Penrose’s circle. “Juxtaposition by us of a Schiaparelli dress with outrageous behavior or conversation simply carried the beliefs of surrealism into public existence.” The group’s predilection was an early form of performance art, similar to that of the Pre-Raphaelites, who mirrored their aesthetic and lifestyle in their mode of dress.

In 1939, when war was declared between Britain and Germany, Miller decided to stay in London with Penrose. “My mother had a hard-wired sense of peace, freedom and justice, and this was the obvious thing to do for her,” Antony recalls. “‘She was going to use her camera to depict the role of women in warfare.” At a time when British reporters struggled to get accreditation to go to the front lines, Miller, an American, was bizarrely accredited by a fashion magazine, British Vogue, which she had been working for since arriving in London. In a khaki army uniform, comprising loose-fitting trousers and a heavily pocketed shirt that she wore almost uninterruptedly for the next year, she crossed the English Channel less than a month after D-Day.

She wrote powerfully and poignantly about everything she saw, from the devotion of American nurses under fire to harrowing images of women with shaven heads who had been punished for assumed relationships with German soldiers. She made her way to Germany, where she documented the horrors of Buchenwald and Dachau concentration camps. She entered Paris with American troops on Liberation Day, where a room at her beloved Hotel Scribe was immediately made available, and interviewed the writer Colette and photographed Marlene Dietrich and Fred Astaire, among others. By the time she went to Austria and recorded a “heartbreaking” series at a children’s hospital, she was seriously depressed.

She returned to England in 1946 a changed person, never able to wash away the mud of Dachau. When she discovered she was pregnant with Antony, she divorced Bey, married Penrose and moved to Sussex with him. “Her inner life was crumbling,” says Antony, who was born in 1947. “She was deeply traumatized by her war experience and degenerated into alcoholism and depression.” Towards the end of her life, she wrote, “I keep saying to everyone, ‘I didn’t waste a minute all my life,’ but I know myself, now, that if I had it over again, I’d be even more free with my ideas, with my body and my affection.” Antony admired his mother’s eventual determination to fight her alcoholism, and her subsequent career as a gourmet cook, which he believes probably saved her. Nonetheless he remembers her as a dreadful mother.

Yet in everything Miller did, there was enormous originality and wit. With Scherman she shared not only ideas and technical support, but above all the jokes that enabled those who saw unimaginable daily horrors to survive. Perhaps unsurprisingly, one of Miller’s favorite jokes was not exactly about fashion but clothes, in particular the baggy utility knickers that were then making an appearance in Britain. “One Yank and they’re off,” she wryly observed. Miller was unique. As her British Vogue editor Audrey Withers once said, “Who else can swing from the Siegfried Line one week to the new hip line the next?”

Les Parisiennes: How Women Lived, Loved and Died in Paris from 1939-1949 by Anne Sebba will be published by Weidenfeld & Nicolson in 2016. Lee Miller is at the Albertina Museum, Vienna from May 8-August 16; albertina.at. Lee Miller: A Woman’s War is at the Imperial War Museum, London from October 16-January 31, 2016; iwm.org.uk