At the age of 17, Murray heard about an audition for young actors in Bristol, and decided to audition for the experience. The auditions were for the E4 teen drama series "Skins". She impressed the producers of the series and was cast as Cassie Ainsworth, a gentle and creative but self-destructive teenager with an eating disorder. Murray and April Pearson were the first two to be cast on the show. Murray went on to appear in the first two series, from 2007 to 2008. She left at the end of the show's second series to make way for a new generation of characters. On the decision to replace the cast, Murray has said that "it would be really silly to be in a teenage drama if you're no longer a teenager".