He is best known for being a judge on the British television show The X Factor.He is a band manager and managed Boyzone who sold over 20 million copies and had six #1 hits.He managed Boyzone member Ronan Keating who had a #1 hit and sold over 4 million albums. He has also managed Union J, Samantha Mumba, and G4. He has covered for Simon Cowell on Britain's Got Talent and The X Factor USA.In 2004 he became a judge with Cowell and Sharon Osbourne for The X Factor.
The band created was Boyzone, whom Walsh managed to international success achieving 16 top three singles, six of which were number ones, as well as four number one albums, selling more than 20 million copies worldwide.
Keating's career was unaffected by the split, he would go on to sell 20 million records worldwide. Boyzone returned from hiatus in 2007, toured in 2008 and released three more albums, their most recent being 2014's Dublin To Detroit.
On October 10, 2009, Boyzone's Stephen Gately died suddenly in his sleep, at the age of 33.
In the 1990s, Walsh rose to prominence when he formed Boyzone, a pop band defined as "the Irish version" of UK band Take That.
Walsh managed the group to international success, achieving 16 top three singles, six of which were number one, and four number one albums, selling 25 million copies worldwide.