His roles in television include Gary Best in The Bill, Mickey Maguire in Shameless and Damon Hay in Coronation Street.
Griffiths was born in Manchester to a Welsh father and Irish mother, and attended St Mary's RC High School in Astley near Leigh, between 1994 and 1999; it was during this time that he starred in Children's Ward at the age of thirteen.
Aside from his long-running roles in The Bill and Shameless, Griffiths has made guest appearances on Coronation Street, Clocking Off, Waterloo Road and numerous other programmes.
On New Year's Day 2018, Griffiths made a guest appearance in the BBC One soap opera, EastEnders, playing Milo.
In 2020, Griffiths appeared in an episode of the BBC One drama Casualty as Peter Hawker, a man who had suffered a brain injury.