In 2005, he played the title role of Emil in Emil i Lönneberga, a theatrical production based on the popular children's novels by Astrid Lindgren.
In 2007, after an open casting involving 4,000 children, Hedebrant was chosen to play the role of Oskar in Let the Right One In.
Hedebrant played the lead role of Oskar in the 2008 Swedish romantic horror film Let the Right One In.
In 2010, Hedebrant was chosen as the lead role in Amors Baller, a Norwegian romantic comedy directed by Kristoffer Metcalfe. Hedebrant plays Lucas, a Swedish teenager who moves to a small Norwegian town, and falls in love with the goalkeeper on the local girls football team. The film premiered in Norway on 25 March 2011. In 2012, he played the role of Tobias in the Swedish sci-fi drama series Real Humans.
He received a nomination for "Best Performance in an International Feature Film – Leading Young Performers" (with Lina Leandersson), in the 30th Annual Young Artist Awards. Other nominations include "Breakthrough Performer" from the Online Film Critics Society Awards 2008 (won by Lina Leandersson), and "Best Actor" in the 2009 Fangoria Chainsaw Awards (won by Ron Perlman).
