 Horan akaita nhabvu yake yepasi rose achipesana neUSA mumwaka wa1999-2002, asi haana kuhwina imwe kapu kusvika mwaka wa2002-2003, iyo yakauya ichipesana neFiji. Akarasikirwa nenzvimbo yake kuna Reggie Corrigan panguva ye2003 Rugby World Cup uye 2004 na2005 Six Nations Championship, asi kuita kwakasimba kweMunster kwakamuona achidzorera nzvimbo yake muchikwata. Akachengetedza nzvimbo yake ye 2006, 2007, 2008 uye 2009 Six Nations Championship, achitanga mutambo mumwe nomumwe wokukunda kweIreland mumushandirapamwe weGrand Slam. Aivewo chikamu chakakosha cheEddie OSullivans 2007 Rugby World Cup squad. Akarasikirwa nemiedzo yaNovember ya2009 mushure mekuvhiyiwa kwemoyo, uye akarasikirwa nenzvimbo yake kuna Cian Healy, uyo akabata chinzvimbo chakatwasuka-musoro panguva ya2010 Six Nations Championship. Horan akatamba neBarbarians F.C. neNew Zealand Maori panguva yeIrish 2010 Zhizha Bvunzo, asi akavharirwa kunze kwe2010 Mbudzi Bvunzo neruoko rwakaputsika. Akarasikirwa ne2011 Six Nations Championship, asi akasarudzwa muchikwata chekudzidzira cheIreland che2011 Rugby World Cup warm-ups muna Nyamavhuvhu 2011. Akatamba neScotland, asi akakundikana kusarudzwa muchikwata chekupedzisira cheWorld Cup. 