Biggerstaff obtained his first professional acting role at ten, playing the son of MacDuff in a Michael Boyd production of Macbeth at the Tron Theatre, Glasgow. He then joined the Scottish Youth Theatre and spent six years with the group. In 1996, at the age of 13, Biggerstaff secured his first major TV role, playing Young Darren in the BBC production of The Crow Road. At 14 he was cast by future fellow Harry Potter actor Alan Rickman in his new movie, The Winter Guest, as Tom, a mischievous schoolboy. In a 2002 interview, Biggerstaff recalled: "It was while at the Scottish Youth Theatre that I was chosen for The Winter Guest. Alan Rickman popped along one day looking for two boys to accompany him to the coldest place on Earth, Fife, for two months to make a film. Myself and the suspicious character that is Douglas Murphy were the lucky ones." Rickman later recommended Biggerstaff to the London acting agency International Creative Management and Paul Lyon-Maris. Within a week, the Harry Potter castings were being distributed. During auditions, the directors suggested that Biggerstaff consider the part of Oliver Wood, and he played the role in the first two films, returning for a brief appearance in Harry Potter and the Deathly Hallows – Part 2. Biggerstaff's career since the first two Harry Potter films has included playing Henry, Duke of Gloucester in the 2004 TV mini-series'; Matt in the world premiere of Sharman MacDonald's stageplay The Girl With Red Hair; and Ben Willis in the short filmCashback for which extra scenes were recorded, and the piece was adapted into a feature released in 2006. In 2007, Biggerstaff played Jeremy Wolfenden in the BBC4 TV movieConsenting Adults which was nominated for BAFTA Scotland's Best Drama Award on 18 November 2007, and won him the BAFTA Scotland's Award for Best Actor – Television. He appeared in the film Hippie Hippie Shake. In 2015 he filmed Whisky Galore! with Gillies MacKinnon and Eddie Izzard In 2016, Biggerstaff played the lead role in French-Canadian Catherine-Anne Toupin's Right Now, a translation by Chris Campbell of À présent, directed by Michael Boyd, which was critically and commercially well received in Bath, London, and Edinburgh. In 2017, it was announced that he would star opposite Georgia Tennant in the Big Finish audio series ', taking the role of Noah.
