Shane Filan was born to Peter and Mae Filan, and grew up in Sligo, a small town in the northwest of Ireland. The youngest of seven children, he has three brothers and three sisters. His parents owned a diner in Sligo named Carlton Cafe located on Castle Street and Shane used to work there as a waiter from a very early age.

Filan attended Summerhill College, a Catholic school, with Kian Egan and Mark Feehily. All three of them participated in a school production of Grease when they were about 12. The Hawkswell Theatre became a significant part of their careers, and as a big fan of Michael Jackson Filan taught himself how to moonwalk.

Before Westlife Egan and Feehily were with Filan in a band known as I.O.U. with other Sligonians Derrick Lacey, Graham Keighron and Michael "Miggles" Garrett. In 1997, he attended an audition for a new Irish boyband, where he was spotted by Boyzonemanager Louis Walsh, and Walsh approached him to join his new venture, Westlife The three Sligonans joined the band along with Nicky Byrne and Brian Mcfadden

Filan, along with Mark Feehily, is the main lead singer (first voice) in Westlife Their first album was released in November, 1999, titled Westlife With Westlife Filan has had 14 UK number ones and six number one albums in the UK, and sold 40 million records worldwide.

Filan has also co-written a few songs, along with the other band members, including: Fragile Heart Bop Bop Baby (Became a hit single and made it into #5 in U.K. singles charts), I Wanna Grow Old With You, Don't Say It's Too Late, Love Crime, How Does It Feel, Crying Girl, Reason For Living, Miss You When I'm Dreaming. He has also written songs for other artists, (together with his former bandmate McFadden): Listen Girl sung by John Ostberg, Let Me Be the One sung by Simon Casey (the song written by only Shane himself), Sei Parte Ormai Di Me sung by Il Divo.

Filan married his childhood sweetheart, Gillian Walsh (Kian's cousin) on Sunday December 28, 2003 at Ballintubber Abbey. A massive Manchester United fan, Filan and bandmate Nicky Byrne proudly wore their Man Utd scarves as they were half time guests at Old Trafford for the game between United and Bolton Wanderers.