Muna Chikumi 1998, Byrne akapinda muhurukuro yebhendi idzva reIrish boyband, uko maneja weBoyzone Louis Walsh akauya kwaari kuti ajoine bhizinesi rake idzva, Westlife. Byrne akabatana neWestlife pamwe naKian Egan, Mark Feehily, Shane Filan naBrian McFadden. Byrne akaburitsa pachena muWestlife: Nyaya Yedu kuti aida kuchinja zita reboka kuWest High; asi vamwe vakasarudza Westlife. NaWestlife, Byrne aive ne25 yepamusoro gumi UK singles, 14 yacho, yaive nhamba imwe, 7 nhamba imwe maalbum uye akatengesa anopfuura mamirioni makumi mashanu nemashanu marekodhi pasi rese. Zvinosimbiswa kuti Westlife vakatengesa mamirioni makumi maviri nemaviri marekodhi nemavhidhiyo muUK mukati memakore avo gumi nemana basa <unk> mamirioni 6.8 singles, mamirioni 11.9 uye mamirioni 1.5 mavhidhiyo.
Kian Egan, Mark Feehily, Shane Filan naBrian McFadden