Gorman was born in Hollywood, California, to English parents. His father was a professor of linguistics at the University of California, Los Angeles in Westwood, Los Angeles. At the age of seven, Gorman moved to London with his family. He has three older sisters. Gorman trained at Manchester Metropolitan University's School of Theatre.
Gorman played William Guppy in the 2005 BBC One adaptation of Charles Dickens' Bleak House, and then appeared as Owen Harper in the first two seasons of the BBC science fiction series Torchwood. Other television roles include Funland and Bonekickers, amongst other projects for the BBC, and he also appeared in Channel 4's political thriller Low Winter Sun. He played scriptwriter Ray Galton in the BBC Four television play The Curse of Steptoe. He has also appeared in television series such as Dalziel and Pascoe, Casualty, Merseybeat, and The Inspector Lynley Mysteries.
Gorman played Jed on the soap opera EastEnders in March 2007. He starred as Hindley Earnshaw in the ITV adaptation of Emily Brontë's Wuthering Heights. In 2011, he starred in Sky1's second Martina Cole adaptation, The Runaway, and in 2014, portrayed Adam, the lead character's stalker and fellow immortal, in ABC's Forever.
On film, he has had roles in Layer Cake, The Best Man, Penelope, Fred Claus, and Cemetery Junction.
Gorman's stage credits include Ladybird (Royal Court), Flush (Soho Theatre), and Gong Donkeys (Bush Theatre), prompting Michael Billington of The Guardian to write that "Gorman proves that he is one of the best young actors in Britain". He has performed in readings, workshops, and development initiatives with the National Theatre Studio, Young Vic, Royal Court, Oxford Stage Company, Paines Plough, and Soho Theatre. Outside London, he has worked with Nottingham Playhouse, the Theatre Royal, Plymouth, and the Royal Exchange and Contact Theatres, where he was nominated for a Manchester Evening News Best Newcomer Award.
From 2008 to 2009, Gorman played Bill Sikes in the West End revival of the musical Oliver!, for which he was nominated for Best Supporting Actor in a Musical in the 2010 Whatsonstage Theatre Awards.
Gorman has played in clubs and on stages all over the world, appearing alongside Neneh Cherry, Rodney P, and Groove Armada. He has worked on music videos and visuals with The Streets. Under the stage name of B.B. Burn, he was part of the human beatbox outfit Drool Skool, alongside Shlomo, DukeBox, and A-Plus (Alex Tew, known as the founder of The Million Dollar Homepage and Calm). Gorman was crowned the BBC 1Xtra Human Beatbox Champion in 2003.
Gorman has been married to Sarah Beard, a schoolteacher, since 17 July 2004. Beard gave birth to their first child, son Max Hugh Gorman, in Cardiff in 2006, whilst the first series of Torchwood was in production. The couple's second child, daughter Nell Gorman, was born on 25 January 2009. A second daughter, the couple's third child, followed in September 2014.