On May 14, 2009, Byrne was a substitute for a Liverpool Legends XI team in a Hillsborough Memorial match. He represented the Republic of Ireland at various youth levels and is a fan of Celtic FC. In 2011, he played in a Celtic Legends XI match against a Manchester United Legends team. Byrne also participated in and won Soccer Aid 2014, scoring a goal in the match.
In terms of music, Byrne joined the Irish boyband Westlife in 1998 along with Kian Egan, Mark Feehily, Shane Filan, and Brian McFadden. With Westlife, he achieved numerous chart successes and sold over 55 million records worldwide. He also co-wrote many of the band’s songs.
In 2016, he represented Ireland in the Eurovision Song Contest with the song “Sunlight.” Westlife reunited in 2018 and embarked on a tour in 2019 to celebrate their 20th anniversary. They also released new music, including the single “Hello My Love” from their album “Spectrum.”
On television, Byrne has hosted and appeared on various shows. He hosted an edition of CD:UK in 2003 and the closing ceremony of the Special Olympics in 2003. He has made multiple appearances on Children in Need and Comic Relief. Byrne narrated stage shows and hosted the Cheerios ChildLine Concert multiple times. He presented the Celebrity Sunday radio program on RTÉ 2fm in 2010 and hosted the reality TV show Football’s Next Star in 2012. Byrne co-hosted the TV talent show The Hit. He also hosted radio shows and a National Lottery game show. Since 2017, he has been hosting the Irish version of “Dancing with the Stars.” In 2020, he hosted RTÉ Does Comic Relief, and in 2021, he was announced as the host of the singing competition Last Singer Standing.