O'Brien grew up in nearby Royton and was educated at the Bishop Henshaw Roman Catholic Memorial High School in Rochdale. He began acting at an early age and was the star of a BBC TV series Gruey by the time he was 15. He also featured in several other series at the time in one-off or recurring roles. In 1993, he played the role of Craig Lee in Coronation Street and then the role of Lee Jones in Children's Ward. In 1993 he also became a regular in the detective series, Cracker, playing Mark, the son of central character Robbie Coltrane. In 1999 he made his cinema debut with the film Virtual Sexuality and began a reunited with Cracker director Michael Winterbottom for 24 Hour Party People in 2002 and, in '04, for the controversial 9 Songs, which included scenes of genuine sexual intercourse between O'Brien and his leading lady Margo Stilley. His role had earned him the credit of being the only mainstream British actor who has been shown ejaculating in a mainstream UK-produced feature. Since 9 Songs, O'Brien has made two further films with Winterbottom; A Cock and Bull Story and The Look of Love. Recent regular TV roles include Holby Blue and The Syndicate.
9 Songs
(Matt)
Virtual Sexuality
(Alex Thorne)
Elizabeth David: A Life in Recipes
(Charles Gibson Cowan)
Goal!
(Hughie McGowan)
Goal II: Living the Dream
(Hughie McGowan)
The Shock Doctrine
(Narrator (Voice))
Bellman and True
(The Boy)
The Look of Love
(Jimmy Humphries)
Monster Maker
(Matt Banting)
A Cock and Bull Story
(Gary)
24 Hour Party People
(Nathan)
The Watchman
(Lee Simpson)
Peterloo
(Peter Wilkes, a Farrier)
Spike Island
(Poster Vendor)
Holmes & Watson
(PC Smalls)
Cracker: Nine Eleven
(Mark Fitzgerald)
The Following Year
(Ben)
Cracker
Dramarama
The Terry and Gaby Show
Heartbeat
(Neil)
Dalziel & Pascoe
Holby Blue
(Constable Robert Clifton)
Band of Brothers
(Allen Vest)
The Last Enemy
(Wafa)
Life on Mars
(Davie Mackay)
Love Life
(Dez)
Messiah
(Eric Metcalfe)
New Tricks
(Michael Jacobs)
Burn It
(Andy Grimshaw)
Cuckoo
(Goran)
Cracker
(Mark Fitzgerald)
Vera
(Bobby Salter)
Blue Murder
(Terry Camerton)
Moving On
(Shane)
Prey
(Phil Prentice)
Secret Diary of a Call Girl
(Al)
Bluestone 42
(Nutsack)
Casualty
(Chris Miller)
Casualty
(Billy)
Children's Ward
(Lee Jones)
The Afternoon Play
(Sean Tyler)
In the Dark
(DS Gary Kenny)
Cracker
(Mark)
Glue
(Thomas Bray)
Jason and the Argonauts
(Actor)
Indie Sex
(Self)
The Cars That Made the World
(Self - Narrator)
Star Wars: Andor
(Pegla)
Years and Years
(Woody)
Chernobyl
(Khodemchuck)
The Family Pile
(Stuart)
Trucking Hell
Death in Paradise
(Danny)
Bloodlines
(Mark Hopkin)
Ted Lasso
(James Tartt)