In 1993, Graham – who had previously been a member of the band Ivory – auditioned to be a member of a new boyband which would later be known as Boyzone, where he sang Meat Loaf’s “Two Out of Three Ain’t Bad”. Although he was not chosen as part of the final line-up, manager Louis Walsh changed his mind after firing two members for their lack of commitment.

In 1998, Graham broke into acting when he played Mikey Oprano the leader of a drugs gang in the full length Irish martial arts film Fatal Deviation, a low-budget cult film produced and set in Trim, Meath. Comedy website Cracked.com nominated Fatal Deviation as the worst movie ever made saying; “you could replace film school with this movie alone–just screening it once for students and asking them to list all the things it did wrong. Anyone who doesn’t write “everything” instantly fails”.

Graham gained a reputation as ‘the quiet one’ in the band. However, despite their success, he felt that Boyzone’s pop-styles did not give him a chance to expand his own musical taste which included rock and folk. (“Creatively and musically, what I wanted to do personally wasn’t what was required for the band’s product, so that suppression of what I wanted led to low self-esteem.”) Following Boyzone’s split in 2000, he sank into depression, but gradually recovered. During his break from Boyzone, he trained as an actor in America, and studied Music Technology and Sound Production after his solo career as a singer failed.

Graham and Karen Corradi married in August 2004. He has two daughters Sienna (born 18 March 2006) and Hannah (30 April 1996) from a previous relationship.

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. Then he toured with Boyzone in 2009 and a brand new studio album with two singles in 2010, “Gave It All Away” and “Love Is a Hurricane” were released. In 2011 he joined his band mates to tour in 2011 and again in 2013 with a new album.

Graham appeared in the 2008 low budget Irish feature film Situations Vacant written by Steve Murray and directed by Lisa Mulcahy who is best known for directing Irish Television drama The Clinic, and was also among the ten Irish actors who appeared on the RTÉ reality show Hollywood Trials

On the BBC television programme Something for the Weekend, Graham’s bandmate Ronan Keating let slip that Graham would be taking part in the fifth series of Dancing on Ice, starting in January 2010. On the show he was paired with professional skater Melanie Lambert, but were voted off on 7 March in a skate-off with Danniella Westbrook and her partner Matt Gonzalez. On participating, Graham has described his training as therapy which has helped him come to terms with the death of his bandmate Stephen Gately, who had participated in the show two years earlier.

In February 2010 it was announced that Graham would be participating in Eurosong 2010, Ireland’s final to select their Eurovision Song Contest entry. He performed the self-penned song “Baby, Nothing’s Wrong” on 4 March on RTÉ One, attempting to achieve an eighth victory for Ireland in the competition, but placed second, losing out to Eurovision 1993 winner Niamh Kavanagh.

In 2013 he appeared in Celebrity Apprentice Ireland on TV3.