When, in the early 1980s, Marc Quinn was still a reluctant art and art-history undergraduate at Cambridge, his contemporaries called him Mad Marc behind his back, an allusion to his intense stare and long flowing hair – the hair of an aspirant Viking, a fellow student told me.

Since then, the man, the stare and the hair have altered radically. The more cemented his reputation, the more subdued, confident – perhaps more grown-up – the artist has become. He has agreed to talk toThe Times about his show, Evolution, which opens this week, and, perhaps tellingly, also to Tatler, which has photographed the artist in aHello!-style portrait with his wife Georgia Byng (sister of the Canongate Books founder, Jamie, and daughter of “a successful Establishment figure” – Thomas Byng, the Eighth Earl of Strafford). We also learn that Quinn attended the boarding school Millfield and that prices for his forthcoming work are expected to reach £700,000. “It is what it is,” Quinn says, and later: “Obviously we live in a media world.”

Those who knew him in the late 1980s will remember a man crazy for drinking. But since 1993 alcohol and, subsequently, cigarettes have been banished; the hair has been cropped short at the sides and razed by a baldness gene on top; he goes to the gym. The temperament, too, has changed – although he denies this. A journalist interviewing him in 2000 describes him as “paranoid”, and, in the years between “mad” and “paranoid”, the word most often used to sum him up was “self-obsessed”. How could he not be, it was reasoned – all he ever did was sculpt images of himself: an imprint of his body in latex; his naked form in lead.

The breakthrough piece, shown at Young British Artists II, and later sold by Charles Saatchi for £1.5 million, was called Self, a cast of his head in nine pints of his own blood. “Outlandishness can’t make up for witlessness,” was the art critic Andrew Graham-Dixon’s verdict at the time. “The head-shaped plasma ice-lolly has novelty appeal, and that is about it.”

He made self-portraits with his own excrement, and of his own erect penis. In retrospect Quinn says of that period: “I find it slightly embarrassing to have used myself as a model, because people inevitably think it’s some kind of egotism or that it’s about confession or self-analysis, and that wasn’t really what it was about. It was about having yourself as the most available model and also as a starting point.”

Of the YBAs – if we can still call them that now that they’re in their forties – Quinn is reputedly the least obnoxious and the most self-contained, still churning out the work and raking in the accolades but no longer living the stereo-typical artist’s life at full tilt – “a gossip-free zone” one curator told me.

He doesn’t seem remotely self-obsessed to me. Nor creepily intense. Serious and focused would be more suitable adjectives, as well as unshakably confident (he’s all for allowing oneself the possibility of failure as an artist but “I don’t think I’ve ever failed”. ). He arrives at his immaculate white studio from the foundry in a bright red boiler suit and promptly changes into fresh clothes to give me the tour of his work for his White Cube show.

Another Times journalist once described Quinn as emanating the aura of a web or graphic-designer and I think that’s accurate. He’s 43 and wears combat trousers, the badge of all men over a certain age in creative industries; his fingernails are clean. Patiently he answers my questions. On why he gave up alcohol in 1993: “Because I wanted to live rather than die, I suppose.” On Brian Sewell: “It would be terrifying to get a good review from him, wouldn’t it?” On having failed his art O Level (for which he submitted two shoes and an airplane sick bag filled with concrete): “I just think art is not something you can put through an exam because anything interesting is exactly what they wouldn’t want in an exam.”

He never graduated from Cambridge because by the time he’d been accepted he’d worked with the sculptor Barry Flanagan and knew that he wanted to be an artist. Two years later he met the gallery owner Jay Jopling and within a decade he’d made his mark.

After the self-portraits, Quinn produced an eclectic, predominantly figurative body of work that some critics say has been inconsistent in quality – a giant sculpture of Darth Vader’s head and casts of dead animals were received lukewarmly. And the kindest thing I can think to say about his chocolate sculpture of Delia Smith’s head is that at least it was biodegradable.

But then he’s back with a strangely lovely frozen garden consisting of plants that could never grow together in nature. His cast of his own son Lucas’s head caused ripples because Quinn had made it with his son’s Magimixed afterbirth. He claims to be surprised that his work with blood or faeces or placenta has been described as unsettling or macabre. “We’re so alienated from the biological reality of our insides, we’re very happy that the cultural reality we’ve formed is the only reality, and sometimes things that make you question that are uncomfortable, and they go ugggh.

“I don’t make things to shock people,” he insists. “I didn’t make it to get a reaction, I made it to have an emotional contact with people, and everybody’s going to have a personal reaction.”

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