Born to Brendan and Noeleen Lynch, a mechanic and housewife, respectively and raised in Donaghmede, North-east Dublin, Lynch struggled with his education during his school years due to dyslexia, but excelled at sports and was a motor racing enthusiast, winning the Portuguese BMX Championship at fourteen. It was around this period he was expelled from school and began to work with his father as a mechanic.
In 1993, music manager Louis Walsh, who had managed Johnny Logan, held auditions in Dublin to find a new boyband to rival British group Take That. Lynch was among the hopefuls present, and was eventually selected. Before even recording any material, he and five other successful auditionees made their infamous appearance on RTÉ's The Late Late Show with Gay Byrne. Although their performance was criticised by the Irish press, the band became one of the most successful pop bands in Ireland.
Lynch quickly became the most distinctive member due to his body piercings, tattoos and violent outbursts which contrasted with the band's clean-cut image. In 1999, he attended the MTV Europe Music Awards with the band, wearing a tracksuit which clashed with his colleagues suits, and shocked the audience by announcing, "There's been a load of fucking shite about Boyzone, but we are not breaking up." (While Boyzone never officially disbanded, they failed to release a single after 1999, until they re-formed in 2007). Later that night, he was involved in a physical brawl with American rapper Puff Daddy. Two years later, at a live concert for Childline, Lynch turned to the camera and yelled: "Tabloid newspapers, you can kiss me fucking arse!"
In 2007, Boyzone reunited, completed a 29-date reunion tour, and released their comeback single on 29 September 2008, Love You Anyway, which was followed by a Greatest Hits album entitled Back Again... No Matter What released on 13 October 2008.
Lynch has become an actor in recent years. In 2004, during his break from Boyzone, he played Eli Knox the chairman of Harchester United in the Sky One football drama, Dream Team. He has also appeared in pantomime, and starred in Snow White and the Seven Dwarfs at the Wycombe Swan in High Wycombe, during the 2004 and 2005 Christmas seasons. In 2006, he starred in Cinderella at the Tameside Hippodrome as Prince Charming alongside Sue Jenkins as the evil stepmother Baroness. In 2016 he starred as Abanazer in the Blue Genie production of Aladdin at The Whitley Bay Playhouse.
A keen motor racing enthusiast, Lynch raced a Marcos, TVR and then Mosler from 2002 to 2006 for the Eclipse Motorsport team in the British GT Championship, and came within a few laps of winning the 2003 British GT Championship at the last race of the season at Brands Hatch when he crashed into a spinning backmarker he was lapping. In 2005 he was involved with the 'Christians in Motorsport' team and competed in the British GT Championship Silverstone round. Lynch addressed a crowd of race fans at the team marquee about how his faith helps him in racing and in life generally.
Lynch is now involved in drifting, competing in the British Drift Championship for performance parts manufacturer & race team Team Japspeed. In 2008 he was involved in an accident with team-mate Danny Eyles while competing in the European Drift Championship round at Silverstone and, although he was not injured, both Nissan Skyline cars were written off.
For the 2016 season of the British Drift Championship, Lynch and Team Japspeed debuted a brand new VH45 V8 powered Nissan 370Z, achieving a second place finish on debut at Lydden Hill.
Lynch has taken part in several reality television series. He was in the second series of the Channel 4 reality television show, The Games 2004, and received a gold medal. Lynch was also in the second series of ITVs Love Island, but left after the fifth week. In 2007, he competed in the second series of Sky One's Cirque De Celebrite.
In 2000, Lynch teamed up with bandmate Keith Duffy and released a novelty version of the Milli Vanilli song, "Girl You Know It's True", as Keith 'N' Shane. They re-wrote the verses in which the original was critical of today's music, but the chorus was kept the same.
In early 2005, Lynch released the song "Don't Go" which was originally a 1988 hit for the band Hothouse Flowers. The same year, he was announced as one of the judges on RTÉ's The All Ireland Talent Show, a reality contest which is modelled on Britain's Got Talent. In 2010, he announced his decision to quit.
In 2008, Lynch published his autobiography The Chancer, which focused on his early years, pop reign, his marriage to Easther Bennett, and newly found Christianity. In May 2011, Lynch became involved with the launch of a new energy vodka called "Ver2Vodka".
At the end of 2012 Lynch, along with friends Ben Ofoedu, Kiz (KizMusic) and Paddy, started a new music project called Cruise Control. Their first song "Raindrops" hit YouTube by storm reaching over 50,000 hits in two weeks until YouTube pulled it offline. Cruise Control then announced on Christmas Eve of 2012 that their first song "Raindrops" would be available for free download. Cruise Control stated that they had big plans for 2013 and had an album waiting for release.
In January 2013, Lynch fronted an informative channel 5 programme in the UK about dyslexia. During this, he undertook his own dyslexia assessment. He was confirmed to have the learning disability.
On 7 June 2013, Lynch featured on a celebrity special edition of The Jeremy Kyle Show to talk about his life after being in boyband Boyzone.
In August 2013, he came fifth participating in Celebrity Masterchef.
In April 2014, Lynch forged a business partnership with Northern Ireland businessmen Dwaine Smyth and Michael Dowall and opened a chain of 1920s prohibition inspired barbershops, known as The Elk & Clipper. There are currently 3 outlets in Northern Ireland with further expansion plans in the future.
Lynch's sisters, twins Keavy and Edele Lynch, found fame as members of the girl group B*Witched, which became the first group to replace members of their own family at number one in the charts. Younger sister, Naomi, was part of the duo Buffalo G, who achieved a top 20 hit, and another sibling, Tara, was a member of FAB!
On 8 March 1998, Lynch married Easther Bennett, lead singer of Eternal, but they separated in July 2000. Lynch and singer Sheena White were married in Ireland on 22 August 2007, and on 25 October 2008, White gave birth to their daughter Billie Rae. Shane and Sheena celebrated the birth of their second child in September 2012, another daughter whom they named Marley Mae.
Lynch, who had been involved with clairvoyants and ouija boards and claimed to have been frequently visited by evil spirits who tortured his mind in his teenage years, became a Christian in 2003; he was persuaded to convert by close friend Ben Ofoedu, who was his colleague in the band REDhill which Lynch joined after Boyzone. Of his bandmate Stephen Gately who died in 2009, Lynch, who was a pallbearer at Gately's funeral, has said: "I've got faith and respect for God - God doesn't make mistakes. So therefore, I've got to understand that it's all for a reason. If I don't understand why then one day I'll be told - but not right now... life doesn't stand still for nobody."