As a resident of Shrewsbury Road, the property financier is no stranger to high house prices and well-todo neighbours. Last year, a family home on the upmarket Dublin street sold for 58m, while another house, a neighbouring 7,000 square-foot pile, later sold for 30m.

The former tax inspector has made a fortune from his now legendary wheeling and dealing on behalf of investors and he has been busy seeking out investments for his cash.

The purchase of a New York townhouse for 22m is probably just one visible sign of how much money Quinlan has made in recent years.

Quinlan often takes a large slice of Quinlan Private's deals himself, in part to show his commitment to deals that are then marketed to the company's wealthy investors.

"My philosophy has been to buy prime, " Quinlan told a British newspaper last year when discussing his company's investment strategy, and it seems he also applies this maxim to his personal purchases.

The new five-bedroomed house is on the same street as Quinlan Private's New York office, which is located at number 54 East 64th Street.

It was bought last year for 16.7m and opened for business in December. And what better way to seal new deals than to leave the office with clients and make the short stroll up the road towards Central Park to bring them home for some cocktails or dinner?

The townhouse at East 64th Street, which once featured in an edition of the glossy Architectural Digest, puts Quinlan firmly on the New York map, in more ways than one.

The house was bought from investment banker Roberto de Guardiola and his wife Joanne, an interior designer. Both confirmed socialites, the de Guardiolas are often guests at and hosts of lavish charity events. Quinlan will probably be much more low-key on the wider social circuit.

But if he is keen to expand his wealth management services into the US, there is probably no better way to impress his pedigree and acumen upon potential blueblood investors than by claiming ownership of a piece of 19th century New York history.

Manhattan's East 64th Street, and others like it, are home to the roots of the city's old money. Some of the homes were built during the American civil war, a time when the Irish in New York were a different breed altogether.

Quinlan Private has already acquired investment property in the United States, buying a Chicago office block last year for $100m.

The company, which owns more than 100 properties valued at about 5bn in total, is in the process of doubling the size of its operation over the next 18 months and has opened new offices in New York and London. The firm, which is planning to increase staff numbers to 100, also recently hired a new chief executive, Olan Cremin, who will oversee the international expansion. Cremin is the former head of private banking at Irish Intercontinental Bank.

At home, Quinlan has also made high-profile investments. Last year he paid an undisclosed amount to buy a stake in the Clarence Hotel on Dublin's south quays. The hotel was owned by U2 band members and impresario Harry Crosbie. Northern Ireland property developer Paddy McKillen, a friend of Bono, also acquired a stake. It is understood he and Quinlan hired a London architect to revamp the property and have also bought an adjacent site so the hotel can be expanded.

It is all a long way from his days at the Revenue Commissioners, where a top-ranking tax inspector today can expect to be earning about 55,000. The annual property tax bill on Quinlan's new townhouse is currently about $80,000 ( 66,000).