Blood's first acting role came in the 25th series of The Bill in a two-episode story of an armed robbery at a toy shop.
Blood made his professional stage debut in 2009 in The Priory as Adam, at the Royal Court Theatre which ran from 19 November 2009 to 16 January 2010. In 2010, he went on to perform as Sordido in the modern adaptation of the Jacobean tragedy Women Beware Women at The National Theatre, directed by award-winning Marianne Elliott.
He had a role as Alex, Ali's gay flatmate who works as a designer, in the BBC drama Material Girl (2010).
In 2011, he appeared in Backbeat which told the story of the formation and early years of The Beatles. It ran in the Duke of York's Theatre from 10 October 2011 to 18 February 2012, and Blood played the lead role of the "fifth Beatle" Stuart Sutcliffe. Due to the musical nature of the role he has learned to play bass guitar, and also subsequently joined a band, Shaaark. The show was an overwhelming critical success during its West End run. This success took the show to Toronto, Ontario, Canada, from 24 August 2012 to 31 August 2012, for a run of seven days.
In 2012, Blood gained his first feature film role as Davy Famous in Spike Island.
In 2013, he appeared in the final season of Him & Her as Becky's ex-boyfriend, Lee. Him & Her appears on BBC Three. Lee is a charming young lad which Becky's parents adore very much and prefer to be Becky's boyfriend more than Steve, who is played by Russell Tovey, and is Becky's fiancé. In 2014, Blood appeared in ITV's mystery drama The Bletchley Circle, as Ben, a police officer. Blood also appeared in the Channel 4 police comedy-satire Babylon. He also provides a voice in the video game Dragon Age: Inquisition.
