In one of the most famous photos of the 20th century, Marilyn Monroe stands on a subway grate, trying to hold her skirt down as a gust of wind blows it up, exposing her underpants. The photo was taken in New York on 15 September, 1954, in a photoshoot during the filming of The Seven Year Itch.

Marilyn is a vision in white, suggesting innocence and purity. Yet she exudes sexuality and transcends it; poses for the male gaze and confronts it. The photoshoot was a publicity stunt, one of the greatest in the history of film. Its time and location were published in New York newspapers; it attracted a crowd of 100 male photographers and 1,500 male spectators, even though it was held in the middle of the night to avoid daytime crowds. Sam Shaw, the stills photographer for the m ovie, took the famous photo, but the other photographers there shot hundreds of variations.

Billy Wilder, the film's director, did 14 takes – pausing between them to let the photographers shoot. Every time Marilyn's skirt blew up, the crowd roared, especially those up front, who could see a dark blotch of pubic hair through her underpants, even though she had put on two pairs to conceal it. The draconian 1934 Motion Picture Production Code forbade such a display. Any sign of pubic hair in photos had to be airbrushed out.

The scene in the shoot is naughty, with the phallic subway train, its blast of air, and Marilyn's erotic stance. Yet she is in control. She is the "woman on top," drawing from the metaphor for women's power that runs through Euro-American history. She poses for the male gaze, but she is an unruly woman – the white witch with supernatural powers; the burlesque star in "an upside-down world of enormous, powerful women and powerless, victimised men". In the photo Marilyn is so gorgeous, so glamorous, so incandescent – as her third husband, the writer Arthur Miller, described her – that she seems every inch a star, glorying in her success. She can now defy the people who had mistreated her: her father and mother, who abandoned her; foster parents who abused her; Hollywood patriarchs who regarded her as their toy; even Joe DiMaggio, then her husband, who physically abused her. Present at the shoot, he stalked off in a fury when her skirt billowed up and revealed her underwear.

In her only discussion of the shoot – a 1962 interview – she stated that she wasn't thinking about sex when she posed, only about having a good time. "At first it was all innocent and fun," Marilyn said, "but when Billy kept shooting the scene over and over the crowd of men kept on applauding and shouting, 'More, more Marilyn – let's see more." Then Billy brought the camera in close, focusing on her crotch. "What was supposed to be a fun scene turned into a sex scene." With her wry humour, Marilyn added: "I hope all those extra takes are not for your Hollywood friends to enjoy at a private party."

We are not accustomed to seeing Marilyn Monroe as being on top in any but the most superficial way. We view her as irreparably damaged, too victimised to have played much of a role either in launching her career or reinventing herself on the silver screen. Nothing could be further from the truth. Marilyn is a woman who made herself into a star, conquering numerous disabilities in the process, creating a life more dramatic than any role she played in films. Her disadvantages were many. She suffered from dyslexia and from a stutter more severe than anyone has realised. She was plagued throughout her life by horrible dreams that contributed to her constant insomnia. She was bipolar and often disassociated from reality. She endured terrible pain during menstruation because she had endometriosis. She broke out in rashes and hives and eventually came down with chronic colitis, enduring abdominal pain and nausea.

She surmounted all this, in addition to the well-known problems of her childhood –a mother in a mental institution, a father she never knew, and moving between foster homes and an orphanage. Then there were the drugs she took to cope, once she entered Hollywood and had to endure its pressures: she especially took barbiturates to calm her down; amphetamines to give her energy.

She had affairs with many eminent men – baseball great Joe DiMaggio, playwright Arthur Miller, director Elia Kazan, actor Marlon Brando, singer Frank Sinatra, the Kennedy brothers – and she married DiMaggio and Miller. Yet she desired women, had affairs with them, and worried that she might be lesbian by nature. How could she be the world's heterosexual sex goddess and desire women? How could she have the world's most perfect body on the outside and have such internal imperfections? Why was she unable to bear a child? The adult Marilyn was haunted by these questions.

Yet in her career she exhibited a rare genius. Publicists marvelled at her ability to generate publicity; makeup artists saluted her skill at their craft; photographers rated her one of the greatest models of their age. She studied with top acting, singing and movement teachers to create her era's greatest dumb-blonde clown. Voluptuous and soft-voiced, the Marilyn we know exemplified 1950s femininity. Yet she mocked it with her wiggling walk, jiggling breasts, and puckered mouth. She could tone her blonde bombshell image down, project sadness in her eyes, and, like all great clowns, play her figure on the edge between comedy and tragedy.

There were many Marilyns. As a pin-up model early in her career she posed for her era's most famous pin-up photo – a nude that became the centrefold for the first issue of Playboy in December 1953. By mid-career she created a new glamour look that combined the allure of the pinup with the aloof, mature sensuality of a glamour star of the 1930s like Greta Garbo. Another Marilyn had a talent for drama, evident in films like Clash by Night (1952) and Bus Stop (1956) and in her poses for photographers like Milton Greene and Eve Arnold.

Marilyn was nothing if not complicated and in ways that have never been revealed. She was shy and insecure, lacking self-confidence. But she was tough and determined. She had an ironic and sometimes ribald wit, engaging in puns and wordplay. She could swear like a trooper. She loved to play practical jokes. She sometimes was a party girl who did "crazy, naughty, sexy things", including engaging in promiscuous sex, displaying what we now call "sex addiction". In another guise she was a trickster who assumed aliases, wore disguises, and lived her life as though it was a spy story, with secret friends and a secret apartment in New York.

Unlike other Marilyn biographers, except Gloria Steinem, I argue that the sexual abuse she endured as a child was formative in moulding her adult character. We now know that such abuse can produce sex addiction, exhibitionism, and an angry, frightened adult. It can fragment a personality. However dominant, "Marilyn Monroe" was only one persona among many that emerged from and were created by the original Norma Jeane Baker. That happened when Norma Jeane signed a contract with 20th Century Fox in August 1946 and began her ascent to stardom.

The 1950s were a paradoxical era. Americans were exuberant over victory in World War Two and the booming consumer economy, while they were frightened by the Cold War with the Soviet Union and the threat of nuclear destruction, and paranoid about homosexuality and internal communism in the United States. Marilyn's comic style soothed the nation's fears, while reflecting the 1950s "populuxe" style in design, which spoofed consumption and laughed at fears through a populist version of luxury. When she put on her Betty Boop character she was populuxe to the hilt.

Her innocent eroticism and joy made her the ultimate playmate for men in a postwar age worried about male feminisation, as warriors became husbands with the end of the war. Beyond feminisation lay homosexuality, demonised in the 1950s as a perversion that threatened everyone. In her films Marilyn often plays against an impotent man whom she restores to potency by praising his gentleness as necessary to true masculinity, as she does for Tom Ewell in The Seven Year Itch. In real life she often chose powerful older men as partners, overlooking their domineering ways in her quest for a father. As an exemplar of her age, she relates to 1950s rock'n'roll musicians and beat poets that were forerunners to 1960s rebels, as did actors like Montgomery Clift and Marlon Brando, who were both identified with new, rebellious acting styles. From that perspective, joined with her support for sexual freedom, she was a rebel pointing to the radicalism and sexual rebellion of the 1960s.

I was drawn to writing about Marilyn because no one like me –an academic, a feminist biographer, and a historian of gender –had studied her. As a founder of "second-wave feminism" and the new women's history, I had dismissed Marilyn for many years as a sex object for men. By the 1990s, however, a generation of "third-wave feminists" contended that sexualising women was liberating, not demeaning, for it gave them self-knowledge and power. The students I taught were swayed by this. Had I dismissed Marilyn too easily? Was she a precursor of 1960s feminism? Was Marilyn in actual fact a feminist? Is she one of the women who changed the world's attitude toward women?

She certainly took actions that could be called feminist. Her entire life was a process of self-formation. She was a genius at self-creation and made herself into an actress and a star. She formed her own production company, she fought the moguls to a standstill, and she publicly named the sexual abuse visited on her as a child: a major – and unacknowledged – feminist act. She refused to keep quiet in an age that believed such abuse rarely happened and when it did, the victimised girl was responsible. Such self-disclosure would become important to the feminist movement in the 1970s.

She never called herself a feminist but the term wasn't yet in widespread use during her life, and the movement wouldn't appear until a number of years after her death. Hedda Rosten, her secretary and close friend, identified her as "the quintessential victim of the male". Norman Rosten, Hedda's husband, who was equally close to Marilyn, saw her relationship to feminism differently. He contended that Marilyn would have quarrelled with her "sisters" on the issue of sexual liberation. She had achieved the financial and legal gains they sought. And she enjoyed her femininity, recognising its power over men. Marilyn's stance in his eyes sounds like a post- feminist position, which privileges power over oppression and emphasises the power women possess through their femininity and sexuality.

On the other hand, one could argue that it was her fixation with her femininity – and her attitude towards it, sometimes regal and sometimes tormented – that caused her victimisation in the end. No matter how hard she tried, Hollywood and its men refused to consider her as anything more than a party girl and in the end they treated her like a slut they could use with impunity.

She commented that "black men don't like to be called 'boys,' but women accept being called 'girls,' " as though she were offended by the latter term. And she didn't like male violence. That is apparent in the dispute she had with journalist WJ Weatherby over Ernest Hemingway. Weatherby liked Hemingway for his understanding of human nature. Marilyn didn't like his masculine heroes. "Those big tough guys are so sick. They aren't even all that tough! They're afraid of kindness and gentleness and beauty. They always want to kill something to prove themselves!" She praised the young people who were beginning to rebel against social conventions. In her best moments, she saw herself as part of that movement. Yet Marilyn had no gender framework to support her stance, no way of conceptualising her situation beyond her individual self, to encompass all women, whose rights were limited in the 1950s. Had she lived a few years longer, into the mid-1960s, the feminist movement could have offered the concept of sexism as a way to understand her oppression and the idea of sisterhood as a support.

In addition to poets and writers like Rilke and Wolfe, Marilyn was also attracted to Sigmund Freud. For Marilyn, always worried about going insane like her mother, Freud's ideas offered a way to achieve a balanced mind that might keep her from the incarcerations and electric shock treatments her mother had endured. Although she continued to explore mystical alternatives and converted to Arthur Miller's Judaism, she called Freudianism her "religion".

Psychoanalysis became a way of life for her. In New York and after she returned to Hollywood in 1961 she entered into a voyage of discovery, exploring childhood memories, trying to figure out who she was. As was her way, she went to the top of the Freudian networks, choosing therapists who were close to Sigmund Freud's daughter, Anna, whom Freud had analysed himself. She finally consulted Anna Freud herself when she was in London, filming The Prince and the Showgirl. She saw Anna for daily sessions over the course of a week. Her psychiatrist during the years she lived in New York with Arthur Miller was Marianne Kris.

When Marilyn went to Hollywood to film Let's Make Love in 1960, Kris recommended that she see psychiatrist Ralph Greenson on a temporary basis. Greenson had a practice in Beverly Hills with many star patients. He had 15 sessions with Marilyn in February and March. He was appalled by the drugs she was taking, and tried to get her off them. During their sessions, Marilyn poured out her resentments against Arthur Miller. Greenson concluded that she had turned Arthur into a foster parent whom she then rejected. He called her paranoid, but not schizophrenic.

Greenson pulled Marilyn together. And some months later, after she suffered a nervous breakdown on the set of The Misfits and her marriage to Miller ended, she decided to move to Los Angeles to undergo regular therapy with him.

She began seeing him as often as five times a week. He thought she was improving, since she seemed more positive in her outlook and told him she was taking almost no prescription drugs. On 1 June, her birthday, she sent Greenson a telegram: "In this world of people I'm glad there's you." According to friends, she called him Jesus. As she had with Arthur Miller and Lee Strasberg [founder of the Actor's Studio in New York, where Marilyn trained] she was developing a father-saviour complex with him. Their relationship would become a focal point in her life.

Ralph Greenson was considered daring to take on Marilyn. Many psychiatrists wouldn't have treated her because of her suicide attempts. The suicide of a patient – particularly of so famous a patient – could destroy a psychiatrist's career. Greenson liked treating celebrities, and treated many famous performers, including Frank Sinatra and Vivien Leigh. He was well known for his theories about the relationship between therapist and patient, which he published in articles in academic journals and in his 1978 book Explorations in Psychoanalysis, for a time considered the definitive work on the subject.

Recent authors have charged that Greenson had sex with Marilyn. Yet both his theoretical stance and his reactions to her contradict that assertion. In analytic papers Greenson condemned sex between patient and therapist. Marilyn may have attempted to seduce him, but he rejected her. That's what he stated in his paper on the use of drugs in psychotherapy. If he upset her, she obsessed about it – which meant threats of suicide and late-night telephone calls. And he easily upset her, especially when he focused on her neurotic reactions to others. She ranted not only against the people she claimed were persecuting her but also against anyone who acted in a way she considered to be against her interests. Greenson decided at this point that Marilyn was at base an adolescent waif who acted irresponsibly, sulking or throwing tantrums when crossed.

Marilyn had brought the nation's most famous acting teachers to heel; she had done the same to the nation's most famous athlete and its most famous playwright. Now she was facing down a famous psychoanalyst. He was brilliant, as was she. During her time with Greenson she had a recurring dream in which she was running through a cemetery in the early dawn frantically looking for a way to escape. She graphically described the tall headstones and the feel of the dewy grass on her feet, but she never got out of the cemetery. It sounds like an attempt to escape from the death she often regarded as a welcome relief from a painful life, or a warning to Greenson that his therapy wasn't working. On one occasion when he was trying to persuade her to give up drugs, he told her that it was either "Mr Nembutal or me". She replied to him that the drugs made her feel "womby and tomby".

Greenson contended that her ego was so weak that he couldn't analyse her and that he was only trying to help her attain a strong enough sense of self to undergo analysis, which would involve deep penetration into her past. Thus he had her sit up during their sessions; she didn't lie down on his couch and free associate. He needed to have eye contact with her to keep her focused. On one level the personalised treatment he gave Marilyn attests to his creativity, as he held analytic sessions with her in his home, had her stay for dinner, encouraged her to become friends with his family – she became close to his wife Joan and his children – and invited her to his evening music salons.

He has been severely criticised for overstepping the boundary between therapist and patient, a credo in the field, but by 1962 the popularity of psychoanalysis was decreasing with the appearance of new behaviourist therapies and drugs. Greenson felt compelled to experiment with innovative psychoanalytic approaches in order to maintain the method's position as a primary treatment for mental disorders. Yet in taking Marilyn into his home, he didn't seem to realise that he was repeating what others had done: the Kargers (Fred Karger was her voice coach), Chekhovs (Michael Chekhov was Marilyn's acting teacher), Rostens and Strasbergs all had taken Marilyn into their families. Greenson's technique was not, in fact, unique. Becoming a member of families may have been part of her pathology, a way of endlessly recreating the foster families of her childhood, trying to lessen their effect on her by finding better variations of them. And she did believe that everyone around her was manipulating her just as drug addicts often perceive everyone around them to be part of a conspiracy against them. Realising that she was an addict, Greenson may have tried to remove her from negative friendships, a common method of withdrawal therapy. He stated that she masochistically provoked people "to mistreat her and take advantage of her".

He tried to end her relationship with Sinatra, who had been his patient and whose neuroses he knew well. He also dismissed Ralph Roberts, her driver, masseur and friend, for he may have decided that Roberts, a vodka drinker, was enabling Marilyn. He was exhausted by Marilyn and in December 1961 he brought Eunice Murray, a friend of his with some practical nursing experience, into Marilyn's life. After initial hostility, Marilyn found she liked having Murray around because she was never alone, which was something she feared. In the months leading up to her death, she saw Greenson nearly every weekday for a therapy session.

Whichever version of Marilyn's death you believe – and there are many – Greenson was one of the last people to see her alive. In most versions he was called to Marilyn's house at 4.30 in the afternoon of 4 August 1962 to calm her down after an argument – either with her publicist Pat Newcomb or with Bobby Kennedy, depending on which story you trust. He stayed until seven, then left to go to a party with his wife. but asked Eunice Murray to stay at Marilyn's house that night, which she normally didn't do. Eunice checked on Marilyn, either at 10pm or at 3am – again depending on which version you believe – sensing that something was wrong. She looked in Marilyn's bedroom window because the bedroom door was locked and saw Marilyn in a strange position in her bed. Worried, Eunice called Greenson to come over, and he did. He took a poker and smashed a window, so that he could open it and climb in. He found Marilyn dead, lying naked under a sheet and at 4.30am he called the police, telling them that Marilyn had committed suicide.

In the years since Marilyn's death, new theories about how she died have periodically appeared, several implying that Greenson may have been involved in murdering her. But in my view Greenson had no reason to kill her; she was his most famous patient, and her death devastated him. When reporter William Woodfield asked Greenson what had happened on the night of Marilyn's death, Greenson said: "Ask Robert Kennedy." This statement is well known among Marilyn researchers. What isn't known is that Greenson said he always thought Bobby should have admitted to having been at Marilyn's house on the day of her death. Greenson then clammed up and, ever after, denied that Marilyn had been involved with Bobby.

Lois Banner is professor of history and gender studies at the University of Southern California. This is an edited extract from Marilyn: The Passion and the Paradox.