Felix Dennis: Publisher who started out working on 'Oz' and went on to found a lucrative magazine publishing empire

In deep middle age he had established himself as a poet, a spoken-word performer and a millionaire philanthropist, but Felix Dennis, who has died of throat cancer, first impinged upon public consciousness in the mid-1960s as co-editor with Richard Neville and Jim Anderson of Oz, regarded spuriously as a sort of colour supplement to International Times, London's foremost "underground" broadsheet. In its prime, however, Oz leaked to the provinces – and, eventually, overseas – as a vista upon what Swinging London was thinking and doing.

As the decade turned, one edition was surrendered to teenagers (of which I was one). As the subject of the longest obscenity trial in history, this "Schoolkids' Oz" matter seemed to conclude with a decisive victory for the establishment with initial guilty verdicts for Felix, Anderson and Neville – and the shearing-off of their shoulder-length hair.

Both national notoriety – and a financially pain-free old age – lay in a future unimaginable during a postwar upbringing in a south London tobacconist's shop where the Dennis family survived on perpetual mental arithmetic, eking out a low income, forever on the look-out for means of supplementing it (Dennis's father did so as a semi-professional pianist). When times were particularly hard, Felix and his younger brother Julian stayed in their grandparents' mid-terrace house in Thames Ditton where the small backyard was dominated by an outside lavatory and a finger-crushing mangle.

When his father uprooted to Australia and the marriage ended in divorce, Dennis slipped into a quasi-paternal role until his mother remarried. "She was a very strong woman," he recalled, "who set out to prove that her early failure, which is how she must have seen it, was not going to blight her children's lives. She went to night school, trained as a chartered accountant, and turned us middle class."

By then, Dennis was studying at St Nicholas Grammar School in Northwood Hills, where he distinguished himself most conspicuously as drummer with the Flamingoes, a beat group formed with classmates. When he left home at 17 he worked with other such outfits, but worked by day as a department store window-dresser before enrolling at Harrow College of Art. While completing the course, he entered the Oz orbit. In the first instance he sold the magazine on the street, but upon graduation he became a designer under the aegis of Jon Goodchild, the magazine's art director.

From his first contribution to Oz as a writer – a piece about Led Zeppelin's debut album – he climbed the executive ladder to co-editor, and co-defendant when, prefaced by repeated police raids on the Notting Hill offices, the "Schoolkids'" issue prompted the arrest of Dennis and his colleagues.

Passing sentence at the Old Bailey, Lord Chief Justice Widgery was more lenient towards Dennis, who he deemed to be "much less intelligent" than the other two. However, through the oratorical skills of their barrister John Mortimer, all three were free after a week inside and were soon acquitted on appeal.

Taking stock, Dennis founded his eponymous publishing company, making initial hay with Kung-Fu Monthly during a mid-1970s craze for martial arts. "Within six months there was £60,000 in the bank," he said. "At its height, KFM was being published in 14 countries and 11 languages. My proudest moment was signing the deal for a Cantonese language edition. Coals to Newcastle didn't come into it!"

The firm also cracked the US market with Computer Shopper, and so began a flow of similar enterprises over the next 30 years, including Maxim, The Week, Auto Express, Car Buyer and the purchase of IFG Limited, whose products embraced Bizarre, Fortean Times and Viz.

Prosperity granted Dennis a life rich in material comforts and the time and resources to exploit a gift for poetry he discovered when in hospital in 2001. Within a year of penning some couplets on a Post-It note, an anthology, A Glass Half Full, was in the shops, launched by the first of his round-Britain reading tours, billed as "Did I Mention the Free Wine?" after the beverage from his cellar offered to ticket-holders. His verse has been heard since on the radio, and has been the focus of television documentaries on both sides of the Atlantic.

He and RSC actors declaimed it at Stratford-upon-Avon's Swan Theatre in 2003, and a year later in New York in the wake of a second collection, Lone Wolf. Likewise, When Jack Sued Jill: Nursery Rhymes for Modern Times (2004) Island of Dreams (2007), Homeless in my Heart (2008) and Tales From The Woods (2010) were accompanied by in-person promotion.

Much of his output is available in Braille, commensurate with his support for the National Library for the Blind. As pragmatic was the creation of a small wood near his principal home in Warwickshire, which led to his establishing what became The Heart of England Forest in 2011, a conservation charity. Last autumn Dennis planted the project's millionth sapling at a ceremony attended by local and Forestry Commission dignitaries.

As an author, Dennis was to venture into an arguably less altruistic field with 2006's How to Get Rich: One of the World's Greatest Entrepreneurs Shares His Secrets – which also delved into his period of crack cocaine dependency and heedless expenditure of almost £6 million on drugs and women. "I should have liked to get married," he wrote, "but over many decades I have lived essentially alone. I go to sleep when I'm tired, get up when I wake up, have my food prepared when I'm hungry. I can't bear the thought that I'd have to coincide, make an effort. People say it's never too late. How wrong they are. It's way, way, way too late."

In an interview in 2008 Dennis said that in the 1980s he had killed a man who had been abusing a woman he knew by pushing him off a cliff. He later said he had been drunk and talking "a load of hogwash".

During the making of the Felix Dennis: Millionaire Poet programme for Sky Arts in 2012, cancer was diagnosed. During treatment he continued to write verse as well as overhauling his earlier work for Love, Of A Kind, a selection he believed correctly was to be his final book. He rallied sufficiently in the latter half of 2013 to undertake one more tour and a poignant interview on BBC Breakfast TV.

Felix Dennis, magazine publisher and poet: born Kingston-upon-Thames 27 May 1947; died Dorsington Warwickshire 22 June 2014.