In June 1998, Byrne attended an audition for new Irish boyband, where Boyzone manager Louis Walsh approached him to join his new venture, Westlife.
Byrne joined Westlife along with Kian Egan, Mark Feehily, Shane Filan and Brian McFadden.
Byrne revealed in Westlife: Our Story that he had wanted to change the name of the band to West High; but the others preferred Westlife.
With Westlife, Byrne has had 25 top ten UK singles, 14 of which, were number one, 7 number one albums and has sold in excess of over 55 million records worldwide.
It is certified that Westlife have sold 20.2 million records and videos in the UK across their 14-year career – 6.8 million singles, 11.9 million albums and 1.5 million videos.
Byrne also had a number one single in Ireland in 2002, alongside the Republic of Ireland national football team and Dustin the Turkey with the Irish 2002 FIFA World Cup anthem, "Here Come The Good Times (Ireland)".
He also co-wrote many of Westlife's songs.

In early January 2016, it was rumored that RTÉ had internally chosen Byrne to represent Ireland in the Eurovision Song Contest 2016.
Byrne had not yet confirmed or denied such information but announced that he would grab the opportunity with both hands if given.
On 13 January, Byrne was confirmed to be the Irish singer for the 2016 contest in Stockholm with the song, "Sunlight".
He performed in the second semi final on 12 May 2016, but failed to advance to the final.

In October 2018, a video was posted to Westlife's official social media platforms announcing the group's reunion as a four-piece.
In 2019, the group will be headlining "The 20 Tour", named in honour of Westlife's 20th anniversary since its formation and the release of its first single, "Swear It Again", in 1999.
In addition to touring, Westlife will also be releasing new music. "
Hello My Love", the first single from the group's upcoming album, will debut on the Graham Norton Show on 10 and 11 January 2019.
In June 1998, Byrne attended an audition for new Irish boyband, where Boyzone manager Louis Walsh approached him to join his new venture, Westlife. Byrne joined Westlife along with Kian Egan, Mark Feehily, Shane Filan and Brian McFadden. Byrne revealed in Westlife: Our Story that he had wanted to change the name of the band to West High; but the others preferred Westlife. With Westlife, Byrne has had 25 top ten UK singles, 14 of which, were number one, 7 number one albums and has sold in excess of over 55 million records worldwide. It is certified that Westlife have sold 20.2 million records and videos in the UK across their 14-year career – 6.8 million singles, 11.9 million albums and 1.5 million videos. Byrne also had a number one single in Ireland in 2002, alongside the Republic of Ireland national football team and Dustin the Turkey with the Irish 2002 FIFA World Cup anthem, "Here Come The Good Times (Ireland)". He also co-wrote many of Westlife's songs.
In early January 2016, it was rumored that RTÉ had internally chosen Byrne to represent Ireland in the Eurovision Song Contest 2016. Byrne had not yet confirmed or denied such information but announced that he would grab the opportunity with both hands if given. On 13 January, Byrne was confirmed to be the Irish singer for the 2016 contest in Stockholm with the song, "Sunlight". He performed in the second semi final on 12 May 2016, but failed to advance to the final.
In October 2018, a video was posted to Westlife's official social media platforms announcing the group's reunion as a four-piece. In 2019, the group will be headlining "The 20 Tour", named in honour of Westlife's 20th anniversary since its formation and the release of its first single, "Swear It Again", in 1999. In addition to touring, Westlife will also be releasing new music. "Hello My Love", the first single from the group's upcoming album, will debut on the Graham Norton Show on 10 and 11 January 2019.
Nicky Byrne