There were not-so-subtle suggestions last week that Declan Ganley, the multimillionaire Galway businessman who is leading the campaign for a No vote on the Lisbon treaty, is some kind of stooge for shadowy figures in the US military who are hell-bent on derailing European integration.

As the referendum campaign heats up, the 39-year-old is becoming the centre of attention, his motivation and even sources of his wealth being questioned by the Yes side, who perhaps feel this referendum is getting too close for comfort.

Before going public with his opposition to Lisbon, Ganley was warned to expect such flak. You can’t expect to take on the might of the Irish political establishment without suffering collateral damage. With two weeks to go, he cuts a somewhat lonely figure. Other groups campaigning for a No vote — especially Sinn Fein and the Socialist party — have had to be kept at a distance. But apart from Ulick McEvaddy, an aviation entrepreneur whose motives have also been questioned, Ganley’s peers in the business community have not exactly been rushing to his aid.

He was born in London, the eldest son of west of Ireland emigrants. The family returned to his father’s village of Glenamaddy, Co Galway, when Ganley was 13. It was tough, says his old schoolmaster Seamus Walsh, for a lad with an English accent to be plunged back into a “traditionally Irish” area as a teenager. “He was at a disadvantage in that he didn’t have the Irish language. Gaelic football would have a strong tradition here and he didn’t play because he came too late for that as well,” said Walsh. “I found that children coming from England in particular didn’t have the educational foundation to follow up the courses being pursued here.” So the young Ganley never showed his true academic ability, according to his former teacher.

Ganley did find ways to both fit in and stand out, though. “He made his own entertainment,” said Walsh. “He was interested in fishing and in the bog. He cut turf and he sold it commercially. He amused us all.”

The young Ganley’s other interest was the stock market. He boasted about shares he was buying, even though he was just 14. Having completed his Leaving Cert, Ganley was of no mind to move on to third level, but wanted to go into business.

The story from there moves at a dizzying pace. After a stint on building sites in London, he secured a job as a tea boy at an insurance company. From this humble perch he launched an audacious, but ultimately failed bid, to use Soviet rockets to blast western satellites into space. He moved to eastern Europe and made a small killing shipping Soviet aluminium to Rotterdam via Latvia at a time when the rouble was collapsing. According to Ganley, he could buy at $30 (€20) a tonne and sell for $300. Because he never had to pay up front, no capital was required.

He was appointed an economic adviser to the newly independent Latvian government in 1992, then started a forestry business in the eastern European state in 1997, which he eventually sold to Renaissance Capital for an undisclosed sum. In 1994, he appeared on the Irish radar briefly as part of a consortium that bid for the second mobile phone licence, losing out to Denis O’Brien’s Esat Digifone.

Afterwards Ganley founded a Europe-wide telecoms company, Broadnet, which he sold to investors for €50m. In 1998 he started a cable company in Bulgaria which he sold four years later for a reported €18m.

Having made his money, the precocious teenager turned “serial entrepreneur” arrived back at Galway in some style. He bought the former Tuam home of the folk singer Donovan, about half a mile from Glenamaddy. With his American-born wife, Delia, and their four children, he settled into a fairly traditional, if extremely well-heeled, lifestyle in rural Ireland. He is a devout Catholic, a teetotaller and a member of the Reserve Defence Force. As his old schoolmaster puts it: “There’s a touch of the ‘more Irish than the Irish themselves’ about him.”

In the aftermath of the September 11 terrorist attacks in 2001, Ganley devised another business venture, Rivada Networks, to supply emergency response systems to the US military and other clients. It was deployed during Hurricane Katrina at the request of Mary Landrieu, Louisiana’s Democratic senator. The company has a firm contract with the US Northern Command, a branch of the American defence forces.

For the last two years, Ganley has divided his time between Galway and Washington, where he has been developing Rivada, a company of which he now owns 80%. Colleagues describe him as “relentlessly focused”. He is said to survive on little sleep, is always the last person to go to bed and is up most mornings at 6am. Phone calls to employees at 3am are not unknown when he’s travelling. He is described as a demanding boss, but a rewarding one, not without a human touch.

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