Perhaps the most intriguing exhibit in Cindy Sherman’s forthcoming retrospective at the National Portrait Gallery is the first, Cindy Book, a family photo album she began making when she was just six years old. It comprises 26 snapshots pasted on pages torn out of a school exercise book and placed inside stapled-together plain covers that are now stained and discoloured with age. For all sorts of reasons, it is a good place to start.

There is no artifice in the actual photographs. They trace ordinary moments in Sherman’s early life from infancy to adolescence: cute baby pics, family gatherings, snaps of her as a child at the beach and portraits of her as a teenager standing gauchely alongside awkward young men. What is striking is the sense of an almost stereotypical all-American suburban childhood. As is always the case with Sherman, though, nothing is quite what it seems.

In green ink, she has circled herself in each photo and underneath written “That’s me,”. That comma is fascinating, perhaps a child’s grammatical error, yet already implying, as curator Paul Moorhouse notes in his catalogue essay, “an unfolding process”. When Sherman rediscovered Cindy Book as a 21-year-old art student, the process unfolded some more, as she added extra photos to the album and, as she puts it, made “the handwriting seem to grow up along with the images”. Does she consider the original handmade album the beginning of her long and singular art practice (“That’s me, or is it?”) or does it start in earnest with the later intervention?

“The original book is interesting to me because it was more about my fascination with our family snapshots,” she says. “They were kept in a shoebox and, as a child, I loved to pore over them looking for pictures of myself as a baby, but also to identify all these characters that existed before I was born. There was such a big age gap between my older siblings and myself, so I think now I was somehow finding myself in the family through the snapshots. When I came back to the album as a student, that was definitely the more knowing artist coming into play.”

Pages from A Cindy Book, c1964 –75. Photograph: Courtesy the artist/ Metro Pictures, New York

Somewhere between those two creative impulses, one instinctive and psychologically revealing, the other conceptual and wilfully deceptive, may lie the enduring fascination of Sherman’s art. For nigh on 50 years, on the strength of one enduringly brilliant idea – turning the camera on her transformed self in order to exaggerate and illuminate the archetypes that are all around us, so familiar as to go almost unnoticed – Sherman has been hiding in plain sight as one of the great artists of our time. In that time, she has redefined photographic portraiture, her approach being, as her friend the writer and editor Ingrid Sischy noted in 1991, more akin to that of a cinematic auteur. “She’s the director, the producer, the set designer, the costume mistress, and the star as well... In her hands, images aren’t straitjackets but vehicles to show the infinite possibilities of who she could be.”

As the NPG retrospective will show, hers is an art of shape-shifting and disguise, artifice and camouflage. It draws on high and low culture: European and Hollywood films, 1950s television sitcoms, art history, high society, fashion, forensic science, drag, pinups and pornography; the esoteric and the everyday, the glamorous and the grotesque. All her major series are here, from the still resonant Untitled Film Stills, which she began when she first moved to New York in the late 70s, through the controversial Centerfolds, the even more controversial Sex Pictures (surely the most grotesquely provocative images ever exhibited in the gallery), the acerbic Fashion pictures, the History Portraits, the Flappers and the Street Style Stars.

Seeing her creative journey unfold, from her use of cheap wigs and secondhand clothes through her discovery of prosthetics and on to her current Instagram experiments in digital face manipulation, what really fascinates is the consistent cultural resonance of her work. “Sherman’s target is the look of the modern world,” notes Moorhouse, “with whose manufactured character she evidently has a love–hate relationship.” And, if her personas have often echoed the way in which our image-obsessed culture has elevated style and appearance, they have also of late become freighted with new meaning in the so-called post-truth age, as the idea of the blatantly fake has taken on more ominous meaning, becoming an acceptable part of our degraded political discourse.

Untitled #92 by Cindy Sherman, 1981. Photograph: Courtesy of the artist and Metro Pictures, New York

As an interviewee, Sherman is incredibly accommodating, but somehow elusive, upbeat but slightly detached. A friend once memorably described her as having “the banality of a great actress”, which may be a clever way of keeping the world at bay, but one can see why she connected with the art-rocker David Byrne – they were an item for several years – who evinces a similar kind of not quite normal normalness.

Before that, she was married for 15 years to video artist Michel Auder, who was addicted to heroin for most of the relationship. They split up in 1999. She described a subsequent short relationship with struggling film-maker Paul H-O as “real fucked-up”. She is currently contentedly single, sharing her Manhattan loft apartment and her house in the Hamptons with a macaw called Mister Frieda, which she has owned for nearly 28 years. “He’s been the longest companion I’ve ever had,” she said recently, “although it’s like having a perpetual two-year-old.”

Sherman came of age when postmodern theory occupied a place in art discourse that it no longer does; perhaps this is why her work has endured much better than some of her peers: because of its implicit – and sometimes explicit – feminist politics. “I’m not personally articulate,” she says when I mention this. “I don’t even like giving lectures, and I certainly couldn’t debate with anyone, but I have strong personal stances. I couldn’t be an advocate but, through my work, I can be outspoken. What’s also important, though, is that the work is always ambiguous, that it lends itself to interpretation. I’m not a message artist.”

Cindy Sherman and her macaw, Mister Frieda, in 2014. Photograph: Sonia Moskowitz/Getty Images

That much was clear from the start. Likewise the love-hate relationship with her subject matter that Moorhouse identifies. Both, as with her fascination with dressing up, may have their roots in her childhood. Born in New Jersey in 1954 and raised in Long Island, she grew up in thrall to Hollywood B-movies and television sitcoms of the time, many of which portrayed suburban America as an idyll of domesticity, traditional family values and untrammelled aspiration.

“I remember, as a child, being drawn to shows like I Love Lucy,” she recalls, “but, even then, realising the artifice in them, the goofy sentiment of all those perfect mums with the perfect homes and perfect men. Growing up in the actual suburbs made me look at what was being portrayed and realise that it was fake. So I was both attracted and repulsed by those films and shows. I think that paradox somehow found its way into the work.”

The young Cynthia Sherman’s family dynamic was complex. Her father, an aircraft engineer, was 49 and her mother, a high-school teacher, 45 when she was born. She was the youngest of five children, all of whom were much older – 19 years separated Cynthia from her eldest sibling. She first began dressing up as a young child, often in the sanctuary of her bedroom. Was it, I ask, a form of attention-seeking, maybe even a cry for help? “It’s something I’ve talked about in therapy in recent years,” she says, matter of factly. “I know that I wasn’t dressing up to entertain my family. It was more about me thinking, maybe they’ll like me better this way. I guess I felt I wasn’t accepted somehow. My parents had thought they were done with raising children when I came along. I don’t think I picked up on all that until I began talking about it to my therapist.”

In past interviews, Sherman has described her childhood as normal and happy, which is certainly the sense you get from the Cindy Book. However, in one interview, she described her father as “a creep” who “would criticise with hate” and, in another, called him “a bigot” and “racist”. As an adolescent, she experienced family tragedy up close, when her brother Frank took his own life. He had moved back into the family home in his mid-20s and belatedly bonded with his younger sister, who was 15 and had just made the decision to apply to art school when it happened. His death inevitably casts a long shadow. In 2016, when the Observer’s Tim Adams broached the subject, she burst into tears and spoke of her subsequent time at art college as a kind of therapy.

In 1972, she began studying for an art degree at Buffalo State College, where she initially excelled at drawing and painting but, ironically, failing the compulsory photography course because of her lack of technical skills. When forced to repeat it, she came under the tutelage of Barbara Jo Revelle, the first person to make her aware of conceptualism. “She felt that to have an idea was what mattered,” Sherman told the New Yorker in 2000, “and right away that made so much more sense to me”.

At Buffalo State College, Sherman began going out with an older artist, Robert Longo, and it was in their shared apartment that she made the first picture of herself – “stark naked, like a deer in the headlights” – as a way to confront her own suburban prudishness. In 1974, while working as an assistant in the nonprofit gallery Hallwalls she set up with Longo and others, she began turning up to openings disguised as someone else in thrift-shop clothes and makeup, standing quietly and without explanation amid the art works.

The pair moved to New York soon afterwards, living in a loft in Fulton Street in lower Manhattan in the shadow of the newly built World Trade Center, when rents were cheap and the now-gentrified neighbourhood was a ghost town after dark. “I never felt scared walking home at 4am,” she says. “There was no one to rob, so there were no criminals.”

Untitled Film Still #56, 1980. Photograph: Courtesy of the artist and Metro Pictures, New York

At first, she stayed in a lot, dressing up and taking pictures of herself. For a time, she worked as a receptionist in a downtown gallery, Artists Space, again sometimes turning up in disguise – once in a nurse’s outfit, another time as a 1950s secretary. One day, she showed a small selection of her photographs to the gallery director, Helene Winer, who told her she was on to something. It was the beginning of what would become her breakthrough series, Untitled Film Stills, in which she posed as archetypal characters from American B-movies and European art house films: the femme fatale, the bored housewife, the city girl, the vamp.

Despite their postmodern knowingness, those early images still fascinate. The generic female characters she inhabits – furtive film actresses, harassed looking housewives, prim librarians – are ambiguous creations, identifiable as archetypes of femininity but also marooned from their contexts, freeze-framed in some bigger, more mysterious narrative. They are photography as elaborate performance: cerebral, ironic, deadpan. As in all of the series that follow, Sherman is present in the images as photographer, art director and performer, but absent insofar as they tell us nothing about her in the way a traditional self-portrait might. Instead, they are pure persona.

“My early work was more about creating still lifes in a way,” she says. “Over time, it’s become more about portraiture, but it’s never been about self-portraiture because I don’t feel like it is revealing anything of myself. It’s about obscuring my identity, erasing or obliterating myself. It’s not fantasy or pretending or narcissism. It’s not about me.”

Alongside Jeff Wall, whose elaborately staged scenarios echoed traditional documentary photography while simultaneously subverting its style and its supposed truthfulness, Sherman made photography into a conceptual art form by foregrounding its deceptiveness (“I know the camera always lies,” she once said). Though not much commented upon, there is an element of play, as well as playacting, in all she does. “Oh yes. It’s fun,” she says, cheerily. “It’s literally playing in my studio. That’s why I like to work alone, because I can be less inhibited. I often don’t know what I want until the end. It’s very liberating.”

Can she remember the initial thrill of finding her own style, her language? “Initially, it was just me retreating into my room and playing with makeup for fun. It was Longo who told me I should document my transformation from my normal self, which was masculine and boyish, to this vamp. When I did that, people were immediately interested. That’s when I could really say: this is my art.”

The transformation was not altogether straightforward, though, as she elaborates. “I thought I had found my place as an artist, but the problem was that, back then, photography was not a medium that was condoned by the art world. I felt I really wasn’t accepted in the art or the photography world because I wasn’t either.”

When did that change? “Not until the early 90s.” Really? That late? “Oh yes,” she says, still sounding slightly indignant. “I remember, back in the early 80s, I was included in a group show at MoMA and certain collectors saying, ‘I love your work, but I don’t collect photography.’” She pauses and, then, laughing, adds: “In fact, someone said that to me just a few weeks ago in Venice during the Biennale. It still happens, but rarely.”

Untitled #307, 1994. Photograph: courtesy the artist / Metro Pictures, New York/Courtesy of the artist and Metro Pictures, New York

These days, though, it no longer rankles. In 2011, Sherman made headlines when one of her Centrefolds series, Untitled #96, sold at auction for $3.89m, making it the most expensive photograph ever at that time. (It has since been superseded by Andreas Gursky’s Rhein II and Richard Prince’s Spiritual America, but five of her other works feature in the top 20 most expensive photographs of all time.) “I didn’t start to feel super-successful,” she says, “until I did the paintings show.” (She’s referring to the History Portraits, which she completed in 1990, using prosthetics as well as wigs, makeup and period costumes, to recreate the style of old master artworks.)

“I think they sold,” she adds, pointedly, “because they looked like old paintings.” That must have been satisfying, though. “In a way, yes, but their popularity made me feel very guilty. I went straight into the Sex Pictures afterwards.”

The Sex Pictures (1992), alongside an earlier series that has come to be known as her Disaster pictures (1986-89), represent two viscerally angry, but nevertheless complex, responses to her own success in an art market not immune to peddling bad art in the guise of provocation. The latter series is both intentionally tasteless and compositionally intriguing: rotten food, vomit and fake body parts all photographed up-close and large-scale so that, from a distance, they look like abstractions. Intriguingly, she was mostly absent from the meticulously constructed ugliness, appearing as a ghostly reflection, as if aghast at the horror of it all.

For the Sex Pictures, she used prosthetic penises, vaginas, sex toys and distorted limbs ordered from a catalogue of medical dummies used in teaching. “I had already been collecting fake tits and asses for years,” she says breezily, “because I thought that at some point I could do really explicit nudity, but not of myself.”

The work features all the motifs of hardcore pornography but rendered grotesquely unreal and all the more unsettling for that. It was in part a response to the culture wars of the late 1980s, when the National Endowment for the Arts came under intense pressure from the Christian right for funding “inappropriate” work by the likes of Robert Mapplethorpe and Andres Serrano. It was also a riposte to Jeff Koons’s Made in Heaven series, which comprised pornographic photographs of the artist and his bride to be, porn star Ilona ‘Cicciolina” Staller. “I found them so lame and tame and not shocking at all,” she says. “They just made me kind of angry.”

The Sex Pictures leap out of the catalogue for the NPG show, their visceral power to shock and disturb undiminished by the years. Their elaborate unrealness somehow makes them more shocking than Koons’s empty porn pastiche or even the most hardcore photograph by Mapplethorpe. I can’t imagine they were fun to make, though. “I guess in a different way, they were, because I also enjoy doing the really difficult things that people can’t buy. It’s a reaction against the commerce of the art world, because I do feel guilty about it.”

Untitled #204, from the History Portraits series, 1988-90. Photograph: Courtesy of the artist and Metro Pictures, New York

Her work has calmed down since, as has, post-therapy, her life. She remains something of an enigma in the art world, both a product of it and a somewhat reluctant star within it. Her extraordinary success, though somewhat belated, seems to have taken her by surprise and, one senses, precipitated a long period of adjustment. “It all happened to me much faster than it did for a lot of my friends, who weren’t as successful,” she says. “That was difficult for me, but it has passed. I have accepted it more now.”

Nevertheless, her status still rankles even some of those supposedly closest to her. “There are a couple of friends I only see once a year when I have a Christmas party,” she says, “Otherwise, I don’t have anything to do with them because I can feel their resentment so strongly. Even one of my family members is that way.”

She is not, she says, much given to “schmoozing at big, groovy openings”, but is certainly a presence on social media, where her Instagram feed, featuring regular posts of her face bent out of shape via digital manipulation, has 255,000 followers. It is, she says, more about “goofing around a lot” than an extension of her art practice. “Someone showed me an app which people use to make themselves look better online,” she says. “I use it to make myself really not look better.”

If one wanted to measure how deeply Cindy Sherman’s art of disguise has seeped into the public consciousness, you need look no further than an episode of the popular podcast This American Life. In 2012, when MoMA in New York hosted a retrospective of her work, Ira Glass, the podcast host, recalled an encounter in which a woman – upper middle class, aged 55-60, wearing wire-rimmed spectacles – had approached him and his friend in the gallery claiming to be Cindy Sherman. She told them that she came to the exhibition every day in disguise to see how people reacted to the work.

When they quizzed her, studying her face for clues, she became uncomfortable, ending the conversation abruptly by saying that she was not in fact Cindy Sherman. They, of course, interpreted this as a typically Cindy Sherman thing to do. “It made her very credibly Cindy Sherman,” Glass concluded. “But, eEven if it was not her, it was even better!,

When the podcast presenters asked for other evidence of “listener sightings” of Cindy Sherman at MoMA, they received three responses, none of them matching the woman they had encountered. “I knew it was her was when she walked by me after making eye contact for the third time,” one listener wrote. “I saw her eyes and they were the same as the eyes in her work. She looked to be 300lbs in her fat suit...”

Even more intrigued, Glass eventually managed to contact Sherman on the telephone. When told about the listener sightings at MoMA, she sounded fascinated, but replied that none of them was her. But, in a way, of course, all of them were.

Cindy Sherman is at the National Portrait Gallery, London WC2, 27 June-15 September