Chris Evans kicks off the first volume of his autobiography with a Top 10 detailing the various words used to describe him by tabloid newspapers: "Tosser" is at number one, just above "Liar", "Tyrant" and "Drunkard".

For many of us, it is similarly difficult to remember a time when Chris Evans, the bespectacled loudmouth who broke out like a ginger rash over our television screens in the 1990s, was anything other than deeply annoying. He fronted some of the most successful, genre-busting programmes of the last two decades  The Big Breakfast, Don't Forget Your Toothbrush and TFI Friday  as well as making a name for himself as a pioneering radio DJ.

But by the time Evans sold the Ginger Media Group in 2000, netting him £35.5m and making him the highest-paid entertainer in the country, his one-time celebrity had morphed fatally into a profoundly irritating ubiquity. We were tired of witnessing his lazy repartee, his drunken antics and his inflated self-confidence. After he resigned from Radio 1 in a fit of pique in 1997, Private Eye summed up the national mood with a cover photograph of Evans featuring the speech bubble: "I'm quitting while I'm a bighead". When he married 18-year-old Billie Piper and went on an extended two-year bender, he seemed to lose any residue of national sympathy.

So the prospect of wading through a self-congratulatory autobiography (one that runs to two volumes, no less), with its zany orange endpapers and cutesy school photographs, did not exactly fill me with glee. Even the cover image of Evans  semi-crouching in a jeans-and-jacket combo with an expression of enigmatic amusement playing around his lips  was enough to send a mid-90s shudder of distaste down my spine.

For much of the first half of this reasonably well-written book, I struggled to overcome my dislike of the Chris Evans persona. He recalls his childhood in a council estate in Warrington in treacly terms, paying homage to his mother Minnie's meatless hotpot and his "first love" Tina with her "great smile". Distressing episodes, such as the death of his much-loved father from bowel cancer when Evans was 13, are largely glossed over  "There were no tears, just relief"  in favour of humorous anecdotes about paper rounds and playground altercations. A lot of it sounds more like what Chris Evans, the celebrity, thinks his childhood ought to have been rather than how it actually was.

But then, something wonderful happens: Evans discovers radio. His prose hits a new level of fluency, injected with such buoyant passion that it is almost impossible not to be won over. As a teenager, he talks himself into a part-time job as Timmy Mallett's assistant on Piccadilly Radio in Manchester, answering phones and eventually coming up with comic skits to perform on air. It is here that Evans learns the basics of his craft: during a stint on the sports desk, he recalls having to put a piece of paper into the spooling roll of tape each time a goal was scored so they could later cut the tape for the highlights package.

When he was put in charge of presenting his own show, Evans was meticulous in his preparation: "I have always written my radio shows, almost everything of what I intend to say," he writes. "I may not end up saying much of it, sometimes none of it at all, but it's always there if I need it." Soon, he was picked up by GLR and, later, by Matthew Bannister at Radio 1.

Evans is at his best when explaining his craft. It is easy to forget now just how revolutionary his Radio 1 breakfast show was. At a time when most British audiences were used to being talked at by a DJ, Evans made the borders between them much more porous. The audience became part of the show and the production team were invited to join in, emulating the "zoo" format made popular by American shock jock Howard Stern. The atmosphere was that of an extended party at a friend's house, interspersed with music and competitions. As Evans puts it: "We just lived out our lives and then went on the radio the next morning and talked about what we'd been up to."

But as Evans's popularity grew, the preparation fell by the wayside  he was too busy sinking pints at his local and snogging Kim Wilde in a tent in The Big Breakfast garden  and things increasingly spiralled out of control. On Radio 1, he failed to turn up for work the day after a Christmas party. While working on Channel 4's TFI Friday, he blew almost £70,000 on transatlantic Concorde flights for his production team to make a 20-second piece of film about delivering a script to John Cleese in New York. He haemorrhaged money on cars and women and Queen Anne vicarages in the Kent countryside. Most fatally, he began to lose sight of his own absurdity.

All of this is recounted with painstaking honesty and a generous dollop of humility. He cringes when recalling his decision to resign on air from Radio 1: "When it comes to being a DJ, resigning on air is the single most defining quality of the loser."

He recalls his string of glamorous girlfriends and ex-wives with the unabashed surprise of a man who cannot believe his luck and is scrupulously nice about all of them, attributing any break-up to his own failings (frustratingly, this volume stops just before he meets Billie Piper). There is the occasional lapse into therapy-speak ("bad people... can't stand positive people being around: it threatens their equilibrium") and the odd unnecessary quotation from the Dalai Lama, but that is more or less par for the course in any celebrity autobiography.

Most of it is written with verve and humour  one of the best lines concerns his favoured London pub, the Nag's Head in Belgravia: "...originally an old spit and sawdust bar in the early 1800s frequented by stable boys and stable girls who looked after the horses of the upper classes. Now it is mostly frequented by unstable boys and unstable girls who can barely look after themselves."

He might once have been a tosser, a liar, a drunkard and a tyrant, but it is as an autobiographer that Chris Evans seems finally to have grown up.