Andrew Warhola arrived in New York City in 1949 carrying his portfolio of sketches in a tattered brown paper bag. The 20-year-old pictorial design graduate, who was the son of Slovakian immigrants and had grown up among the steel mills of Pittsburgh, was an odd presence among the glitz of Madison Avenue. It didn’t matter. The same year his whimsical style – which was indebted to folk art – landed him a commission for Glamour magazine. Soon after he became one of the most famous commercial artists in the city, producing drawings for Vogue, Vanity Fair and Harper’s Bazaar and lending his work to record sleeves and shop windows. In the spirit of reinvention, he dropped the “a” from his last name.

This phase in the trajectory of Andy Warhol’s career is the focus of Adman: Warhol before pop, a new show at the Art Gallery of New South Wales. “Warhol always had this practice that embraced the worlds of both commercial and fine art and understood them as worlds that pollinate each other,” says curator Nicholas Chambers, who was previously the Milton fine curator of art at the Andy Warhol Museum. “At the time, artists often produced commercial work to sustain themselves as visual artists. The difference with Warhol is that he was openly doing both at the same time. In an interview before he passed away he said, ‘I was always a commercial artist’. This idea continues through the ’50s and the ’60s as well.”

The exhibition features 300 works including never-before-seen drawings, artist books, vintage advertisements and window displays and was produced in partnership with the Andy Warhol Museum in Pittsburgh. It offers an intimate look at an artist before his star-making Factory was a force in the art world, before Double Elvis and Marilyn Diptych made him an icon. But it also shows that aside from blurring the line between art and commerce Warhol complicated these categories from the beginning. His eerily exact Campbell Soup Cans might have sparked the question “Is this art?” in the early 1960s, but his childlike drawings of women’s heels and candy-coloured designs for LPs by Johnny Griffin and Billie Holiday obviously is.

If you’ve always pictured Andy Warhol as a posturing, auteur-like figure strutting around New York in his fright wig and ordering Edie Sedgwick to stay still during his screen tests, the show reveals a tender side to him. A body of drawings of male nudes – one crying, another saying “I love you” – are sensuous and intimate, hinting at the openly queer Warhol’s longing for intimacy. Elsewhere, advertisements for leather-goods company Fleming-Joffe are hand-lettered in cursive by Warhol’s greatest collaborator, his mother Julia Warhola, who he lived with for many years.

“It shows Warhol’s skill as a draughtsperson and highlights a very different set of influences that [don’t usually] come to mind when people think of Warhol’s work,” says Chambers. “You can see traces of people like John Cocteau, even Matisse and Picasso.”

Adman: Warhol before pop reveals Warhol’s relentless appetite for experimentation and his habit of using every medium at his disposal, regardless of whether it was high or lowbrow. It also shows how, through sheer ambition, an outsider from Pittsburgh shaped the visual culture of the late 20th century, somehow ushering in both the cultural moment and chronicling it as it unfolded.

Get our pick of the best news, features and events delivered twice a week

“Warhol was always … really tuned in to media culture, and sometimes he would have a contrarian take,” Chambers explains. “He was also one of the first artists to embrace video and, of course, in the ’70s and ’80s he produced TV shows, music videos for bands on MTV. He was also one of the first artists to use a computer – there’s a series of little-known works he made on an Omega computer in the ’80s. I think he’s an artist that always exploited every possibility.”

Adman: Warhol before pop runs until May 28, 2017.