You could hear a note of righteous anger in Ian Hislop's voice. "Tens of thousands of pounds have been spent on this order," he told listeners to Radio 4's Today programme on Tuesday, explaining how he had forced the BBC journalist Andrew Marr into the open.

Via the pages of the Daily Mail, Marr had confessed his embarrassment at having taken out a "super-injunction" to hide the fact that he had an extra-marital affair – and Hislop had gone on air to point out that it was his magazine, Private Eye, that had forced the high-profile presenter into this act of contrition.

That the costly legal challenge to an extreme gagging order that applied to Britain's mightiest media organisations was taken up by a fortnightly magazine produced on a relative shoestring from a creaking townhouse in London's Soho was surprising. What was less remarkable was that it was Hislop who relentlessly pursued Marr, driving his quarry into the arms of the Mail, the paper that provoked the injunction when it first caught scent of the story more than three years earlier.

For Hislop, though he never trained as a journalist, is as terrier-like as any in that trade. His deputy at the Eye, Francis Wheen, remembers Hislop studying the original legal notice from the law firm Schillings. "I remember Ian got very indignant and said, 'How can they just send us this thing without giving us any indication of what the justification is?' He has been steaming about it all this time. It has been three years of annoyance and indignation that a journalist of all people should be pioneering this weapon of the super-injunction."

Hislop, 50, does not shirk confrontation. Again and again, he has felt unable to conceal his contempt for fellow television-show panellists of whom he does not approve. He went for Neil and Christine Hamilton on Have I Got News for You and criticised Jeffrey Archer on Question Time when sitting alongside the disgraced peer's wife Mary. Piers Morgan was another who he took to task both on television and in the pages of his magazine, provoking a long-running feud.

"It's reasonable that people should dislike me. You have to develop a thick skin. I am much more thick-skinned now than when I first took the job," Hislop told the Oxford University publication Cherwell two years ago. In truth, he had to harden up pretty quickly when, not long out of Oxford, he was appointed editor of the Eye aged 26, the anointed successor of the magazine's co-founder Richard Ingrams. Some of the old guard were not impressed. "I don't think people like midgets, especially pushy midgets," sniffed Nigel Dempster, who with Peter McKay attempted a putsch before Hislop had them both sacked.

The new editor was young in years but not in his ways as he defined his role as to "criticise vice, folly and humbug". Now, having edited Private Eye for 25 years, the young fogey is not about to go shopping for training shoes. "There is a Ross and Brand culture of not growing up to be a man, of remaining a lad into your fifties," he complained to the Daily Telegraph in 2008. "That would have been alien to our grandfathers' generation. They wanted to join the world. They weren't afraid of being judgemental. That's what I'd like to encourage in my son."

The cavalier Piers Morgan couldn't understand such puritanism and sent reporters and photographers to dig dirt in the Kent village of Sissinghurst, where Hislop lives with his wife Victoria, a successful author, and their two children. One of Morgan's team even pleaded with the local vicar for scandal on one of his church regulars. Morgan, who had promised readers of the Daily Mirror a "Hislop Dossier" but produced nothing, later remarked that "barely a day goes by now when I'm not racked with guilt about how I treated this Mother Teresa of journalism". Despite the sarcasm, Hislop's integrity was untarnished.

"You can't run a paper like this unless you accept that there are moral differences," was a rather smug description he once gave of his job. Ian Hislop is a man of conservative tastes, who enjoys himself in summer by playing cricket (he is a decent bat), or by indulging his love for railways. (He travels to the Eye by train and endlessly regales colleagues with the latest excuses for delays.) Most of all his passion is for history. He has proven himself an adept broadcaster, presenting radio and television documentaries on the First World War, the history of the Scouts and the Church of England (which he regards today as a "limp and liberal institution", though he is on friendly terms with the Archbishop of Canterbury).

He lost his father when he was 12; his mother died young and he has described some of the older journalists at Private Eye as "substitute fathers". Describing the origins of the magazine, he once remarked of the founders: "Most of them didn't have fathers."

Hislop's strict moral code has not prevented him from presiding over a title that most readers buy for laughs. The jokes are hatched in the editor's first-floor office where he gathers around him trusted colleagues such as the former editors Christopher Booker and Ingrams and, until recently, Eye veteran Barry Fantoni (who now lives in France). The group tries out gags on each other and the ones that get the laughs are written out in longhand for publication in the magazine. Hislop also writes jokes with an old friend, the cartoonist Nick Newman (with whom he was at Ardingly College, a Sussex boarding school).

As any viewer of Have I Got News for You knows, Hislop has a fast and cruel wit. After university he supplied material to the comic Jasper Carrott and he once wrote lines for the 1980s satirical puppet show Spitting Image . He provided the words for the Harry Enfield character Tim Nice But Dim, which would be a career high for many comedians.

Some veteran observers even complain that the modern Private Eye is sometimes so joke heavy that it is closer to a comic than the biting satirical magazine it began as 50 years ago. But readers still like it – the circulation figures have defied the downturn experienced by most of the publishing sector.

The fogeyish conservative editor has recently embraced text and email but steadfastly resists Twitter and Facebook. He is diligent in personally reading and replying to the reams of readers' mail, though nothing riles him like the sight of a legal letter. "He's not a man to forget a grudge easily," said Wheen. "And nothing infuriates him more than a lawyer behaving badly."

The Schillings warning in the Marr case was particularly sensitive for Hislop because the firm's founder, Keith Schilling, represented Private Eye in Hislop's first major court case, when it was sued by Sonia Sutcliffe, the wife of the Yorkshire Ripper. She was awarded £600,000, and though those damages were later reduced to £60,000, Hislop memorably declared: "If that's justice, I'm a banana."

Since then, Hislop has become the most sued man in English legal history, though he says the rate of libel actions is slowing. Andrew Marr may have backed down in his battle with the Eye, but Ian Hislop – who despises bullies and says satire works best when "you attack the strong, not the weak" – is looking for new targets. These super-injunctions must leave him feeling like a bendy piece of yellow fruit.

A life in brief

Born: 13 July 1960, Swansea, Wales.

Family: His father David and his mother Helen died when Hislop was young. He married Victoria Hamson, a novelist, in 1988; they have two children.

Education: Ardingly College in Sussex where he was head boy. Graduated from Oxford with a degree in English in 1981.

Career: After Oxford he was offered a job at Private Eye. In 1986 he became editor. His TV work includes working as a scriptwriter on Spitting Image and as a team host in every episode of Have I Got News for You since its inception in 1990. He has also appeared in Who Do You Think You Are? and Great Railway Journeys and written shows for Radio 4.

He says: "As a leading BBC interviewer who is asking politicians about failures in judgement, failures in their private lives, inconsistencies, it was pretty rank of him to have an injunction while working as an active journalist." On Andrew Marr