Although Bruce Willis' character is undoubtedly an Irish-American cop, there's a slightly more on-the-nose connection between Die Hard and Ireland that's only recently turned up.
While it's true that there is a village in Kildare called Clane and, yes, we've got a footballer that sounds vaguely similar to John McClane, there's also another connection to John McTiernan's masterpiece.
According to a number of sources, there was a huge, HUGE difference between the German version of Die Hard and the one that basically everyone else saw.
As we know, Hans Gruber and his team of Euro-trash terrorists are initially masquerading as members of the Volks Frei Movement. The anchorwoman (who was also in Lethal Weapon 2, by the way) reports it as such, and then later specifically mentions that they've been excommunicated from the group.
You have to remember that when the film was released back in 1988, Germany was still under terrorist threat from domestic groups such as the Red Army Faction and the Baader-Meinhof Gang. Therefore, having German terrorists parading around the screen and shooting at the guy from Moonlighting wasn't going to fly.
So what did they do? They made Alan Rickman and his band of merry terrorists Irish. Hans Gruber became Jack Gruber, Heinrich became Henry, Karl became Charlie and on it went. Their background changed from being German terrorists going freelance for profit to members of the IRA who left to become mercenaries.
Pretty random, eh? This probably explains why Alan Rickman was cast as Eamon DeValera, considering he already had experience as an Irishman.