MCD's Denis Desmond - the music man who sold us 1.49m tickets last year

"He's hugely important," says Tom Dunne, the Something Happens singer and Newstalk presenter, "and the calibre of live acts that we have long got used to coming to this country is largely down to him."

Desmond's MCD is by far the biggest player in concert promotion in this country, and now the Cork man is set to take the reigns of the UK and Ireland division of Live Nation, the entertainment conglomerate, whose portfolio of blue-chip clients includes U2 and Madonna. Desmond has an existing relationship with the global giant: LN-Gaiety Holdings Ltd, a joint venture between Desmond and Live Nation, is reported to have acquired Mama & Company, the operator of nine UK venues including the Jazz Café in London's Camden, the Borderline in Soho and the Forum in Kentish Town.

The news comes just weeks after Desmond, in partnership with Live Nation, staged a sold-out Electric Picnic boasting more than 50,000 attendees - the biggest in the festival's history.

The success of what's considered Ireland's best festival (which was originally the brainchild of promoter John Reynolds) is seen by many as a marker of Ireland's economic recovery. People are spending serious money on entertainment again, and MCD are among the main beneficiaries.

Last year, the company sold 1.49 m tickets in Ireland - up 165,000 on the previous year. Its fortunes were helped by three One Direction shows at Croke Park, in stark contrast to its main rival Aiken Promotions who were denied a massive windfall when its five sold-out Garth Brooks concerts in the same stadium were controversially axed.

Desmond founded MCD with businessman Eamon McCann in 1980 and the company's name was derived from the two men's initials. McCann concentrated on Northern Ireland; Desmond on the Republic and the pair had a comparatively steady 1980s, with bigger acts coming on stream by the end of the decade thanks to the development of the Point Depot. (The two would fall out spectacularly years later, and end up in court in dispute over profit share.)

The company's fortunes changed forever in 1990 when it staged the inaugural Féile in Thurles, a festival that's now seen as the progenitor for today's big multi-stage events such as Longitude, another MCD creation. Intriguingly, it was local TD Michael Lowry who dreamt up the idea of having a major music event in Semple Stadium, but it was Desmond who made sure it happened.

"That first one was pretty rudimentary but it pulled in far more people than Denis might have imagined," says one associate. "He realised the potential of it pretty quickly and it improved greatly in the space of a few years. He would take in everything he learnt from Féile when it came to launching Witnness a few years later."

Witnness was first held in 2000 and after a change in sponsor became known as Oxegen from 2003. At its peak, which coincided with the heyday of the Celtic Tiger, it catered for 80,000 people, many of them attending festivals for the first time, and would play a major part in swelling the coppers of MCD. It was last held in 2013 and although not officially retired, MCD's festival commitments are now centred on both Longitude and Electric Picnic. "He's always hungry for the next thing," the associate says, "and there's a restlessness to him that keeps everyone who works for him on their toes. He certainly didn't take his eye off the ball in the years after the recession first hit and now that people are spending again, he's reaping his reward."

Tom Dunne says it's "his love of music" that has helped ensure he has enjoyed such a formidable longevity in what's a difficult, and fickle industry. "It's no commodity for him," Dunne says. "He's a music man through and through and that's been obvious in my dealings with him."

It may be a mark of the esteem with which he is held, but few of his former employees are willing to talk about him at all, on or off record. One former staffer speaks of a formidable work ethic that filtered down through the company.

"He expected people to work hard, and if you did you could learn an awful lot in a short time. For me, there was a sense that if you showed initiative you would be rewarded and given real responsibility and there's something very appealing about that because a lot of companies don't operate that way."

While Desmond's abilities to strike a deal are the stuff of legend, he has had his fair share of controversies over the years.

In 2006, he waged war on the message board, Boards.ie, because of commentary surrounding that year's Oxegen festival, while two years later he sued Prince after the singer pulled the plug on a planned Croke Park appearance despite 55,000 tickets being sold; an out-of-court settlement was reached in 2010. More soberingly, Desmond had to deal with the fallout of the Swedish House Mafia concert in 2012 during which one young man was killed and a further seven were stabbed.

For many years, Denis Desmond and his wife Caroline were among the most celebrated power couples in Ireland but they split after she discovered he had been having an affair. "The affair was over by the time I found out about it, but I was crushed," she told a newspaper in 2013.

"We work together and go to things together and we've remained best friends."

Caroline, who now uses her maiden name Downey, runs Dublin's Gaiety Theatre, which MCD owns, and also manages Hozier, the Wicklow singer who has become one of Irish music's biggest exports in years.

The couple have three children - all boasting names more redolent of rock stars: Zach, Storm and Jett. "We built the company for the children if they want it," Caroline says.

Just don't bet against their 63-year-old father stepping down any time soon.