After seven years as a member of Ecofin, the powerful council where EU finance ministers meet, Charlie McCreevy is already a familiar figure in Brussels. He has attended meetings in the EU capital at least once a month since the mid-1990s and has participated in EU summits at least twice a year.
So when McCreevy moves into his Commissioner's office at the Berlaymont building in November, he will face fewer surprises than many of his colleagues. McCreevy's experience at the highest level of EU politics will also endow him with more authority than many of his Commission colleagues.
This experience also means he has a history of relationships with other EU governments and with the Commission itself, of which some have been happier than others.
His old sparring partner in the 2001 budget dispute, Pedro Solbes, is now Spain's finance minister, and other former colleagues have moved on to different posts.
An ideologically driven market liberal, McCreevy is also a political pragmatist who respects the rules of power politics in the EU. As chairman of Ecofin during the first six months of this year, McCreevy took a modest approach, eschewing any attempt to introduce big initiatives or to impose his own ideological bent on his colleagues.
Nonetheless, he arrives in Brussels with a reputation as a tough politician who has a clear view of how Europe can best increase its wealth and improve the lot of its citizens. Many of his fellow Commissioners are likely to share that view because most will come from centre-right governments.
It is impossible to predict what portfolio Jose Manuel Durão Barroso, the new president of the Commission, will allocate to his Irish Commissioner but there will be little surprise if McCreevy wins a major economic post. Durão Barroso may view McCreevy as a liberal ally but Berlin and Paris also know him as a man with whom they can do business.
One group that may not welcome his appointment is the interpreters, who struggle to keep up with his rapid, idiosyncratic delivery.
As an ebullient personality, McCreevy will fit easily into the traditional Irish establishment in Brussels, where entertainment centres on golf, poker and long dinner parties. His experience in Government has also prepared him for the long hours and punishing travel schedule that are an unhappy part of the Commissioner's lot.