Sophie Leris: Join the dots, you'll discover Hirst is a genius

Because he has become so very famous and so very, very rich, sceptics tend to write off Damien Hirst's success as an extraordinary talent for self- promotion. His association with the former ad-man Charles Saatchi doesn't help. But what canny self-publicist would turn down the British Council's offer to represent Britain at the Venice Biennale, as Hirst did, because "it didn't feel right"?

The sale of his most recognisable work, the shark suspended in formaldehyde, to an American hedge fund manager, Steve Cohen, for $12m (£6.5m), makes him the second most expensive living artist ever sold after Jasper Johns, and that is because Hirst is an artist of the very highest calibre. We are extremely lucky to have him. The quality of his work and the powerful intellect behind it has imbued the British art scene with gravitas and a burning excitement that has placed London firmly at the centre of the international contemporary art world. The success of the Frieze art fair, and the international recognition of a group of artists who came to our attention during the 1990s can be laid at Hirst's door; what is most interesting about him, though, and what typifies his generation of artists, the YBAs, is a sense of loyalty and a spirit of generosity that pervades their circle and binds them together even now. With all his fame and wealth, Hirst's first instinct is to exhibit the work of artists he admires, many of whom happen to be friends.

When he curated the seminal student art exhibition "Freeze", while in his second year at Goldsmiths, Hirst established himself as leader of an extraordinarily creative generation. His ambition and persistence, not only on his own behalf but that of his friends, were notable from the off: Norman Rosenthal, exhibitions secretary of the Royal Academy, remembers Damien taking him to "Freeze" in a Docklands warehouse, and again, to visit the studio of an obscure young sculptor called Rachel Whiteread. Eighteen years on, Hirst is showing a selection of works from his own private art collection, Murderme, at the Serpentine Gallery in Kensington Gardens. The exhibition includes Andy Warhol's Little Electric Chair screenprint, a recent acquisition that cost £1.8m, a Francis Bacon (Hirst's most expensive artwork at $12m), and pieces by the US superstars Jeff Koons and Richard Prince, as well as many of Hirst's Britart contemporaries such as Sarah Lucas, Marcus Harvey, Angus Fairhurst, Gavin Turk and Tracey Emin. "In the Darkest Hour There May be Light" is nothing if not democratic. Marcus Harvey, who has known Hirst for 30 years, says he collects "on a personal level. With Damien, it's all about getting to know people, respecting them and supporting them. He is putting a collection together for posterity, for the people who have come up with him, for everyone else to enjoy."

Harvey is referring to Toddington Manor, the stately home in Gloucestershire that Hirst has bought for what was thought to be £3m to house the collection of more than 1,000 artworks.

"Damien has become the collector that everyone wished Saatchi would be," says Harvey. "Saatchi has the attention span of a goldfish and offloads work as soon as he finds something new. Damien's collection doesn't go as wide but it goes very deep. He collects with integrity and he'll never sell."

Hirst's early and on-going preoccupations with life, death, the macabre and the juxtaposition of the coldness of science with the intensity of art - he visited a morgue at 18 - have resulted in work that has changed the face of contemporary art. After "Freeze", he co-curated two more warehouse shows with his friend, the writer and curator Carl Freedman. Saatchi arrived at the latter in a green Rolls-Royce and bought Hirst's first major animal installation, A Thousand Years, which featured maggots feeding off a cow's head, maturing into flies and being zapped to death. Saatchi offered to fund Hirst's next work,The Physical Impossibility of Death in the Mind of Someone Living - the shark. Hirst wanted "a shark that was big enough to eat you, in a large amount of liquid so you could imagine being in there with it." He uses shock as a tool rather than an end in itself, a means by which he is able to make visible his concerns about life and death. "I want to make people think, not to shock the shit out of them for the sake of it," he has said.

As Saatchi continued to fund and collect Hirst's works and Jay Jopling of White Cube became his dealer, his career soared. Unusually, he consciously took his contemporaries with him. Hirst had always swapped work with friends as young, impoverished artists do, but as soon as he began earning he began buying. He continued to curate group shows. In "Some Went Mad, Some Ran Away", at the Serpentine in 1994, his lone sheep in a tank, Away from the Flock, elicited much excitement in the red-tops, not least the Sun, where Norman Tebbit asked, "Have they gone stark raving mad?" Hirst's winning the Turner Prize in 1995 ruffled more feathers, but it was "Sensation", Saatchi's 1997 exhibition of his collection at the Royal Academy, that caused the biggest outpouring of tabloid and public rage.

Curiously, it was forays into good food that really developed Hirst's art collection. "When he had Quo Vadis with Marco Pierre White he was given a chequebook and asked to create a collection for the restaurant," says Harvey. "He started thinking about investing in stuff by the big guys we were gawping over as kids."

It is easy to criticise the mass production element of Hirst's work, the many editions he produces and his spot and spin paintings, most of which are made by a team of assistants. But Hirst runs his company, Science Ltd, much as Warhol ran his factory or a Renaissance artist ran his studio. The abundance of work is indicative of Hirst's ultra-powerful position in the art firmament. Hirst says that the art lies in the conception rather than the execution.

He is worth well over £100m and the money is ploughed back into the art world: he employs over 100 people, most of whom are young artists; he is building a public gallery in south London, investing millions in his collection and the museum, and owns a place in Mexico which is open house to artist friends. He also owns a seafood restaurant in Ilfracombe, Devon, where he lives with his wife and three sons.

"He had this incredible faith, long before anyone of us was ever heard of," says Harvey. "Of course, when he's in a bad mood he's evil."

Thank God for that, or we would never have had all those brilliant, glacial meditations on the hollowness of contemporary culture and the dread inevitability of the death to come.