Mezue ahịrịokwu na-esonụ: Horan mere egwuregwu mba ụwa mbụ ya megide USA n'oge 1999<unk>00 oge, mana ọ nwetaghị okpu ọzọ ruo oge 2002<unk>03, nke bịara megide Fiji. Ọ tụfuru ebe ya na Reggie Corrigan n'oge 2003 Rugby World Cup na 2004 na 2005 Six Nations Championship, mana arụmọrụ siri ike maka Munster hụrụ ya ka ọ nwetaghachi ebe ya na otu ahụ. O jidere ebe ya ruo
2006, 2007, 2008 na 2009 Six Nations Championship, na-amalite egwuregwu ọ bụla nke mmeri Ireland na-emeri Grand Slam. Ọ bụkwa akụkụ dị mkpa nke Eddie O'Sullivan's 2007 Rugby World Cup squad. Ọ hapụrụ ule nke Nọvemba 2009 mgbe ọ nwesịrị ịwa ahụ obi, wee tufuo ebe ya na Cian Healy, onye jidere ọnọdụ loosehead-prop n'oge 2010 Six Nations Championship. Horan gbara Barbarians F.C. na New Zealand Maori n'oge ule oge ọkọchị nke Ireland na 2010, mana ewepụrụ ya na ule Nọvemba 2010 na aka gbajiri agbaji. Ọ hapụrụ 2011 Six Nations Championship, mana ahọpụtara ya na ndị otu ọzụzụ nke Ireland maka 2011 Rugby World Cup warm-ups na August 2011. Ọ gbara bọọlụ megide Scotland, mana ọ họpụtaghi ya na ndị otu ikpeazụ maka Iko Mbaụwa.