In 2013 Mangan played Alastair Caldwell in Rush, a British-German biographical sports drama film centered on the rivalry between race car drivers James Hunt and Niki Lauda during the 1976 Formula One motor-racing season.
In 2014, Mangan voiced the title role in Postman Pat: The Movie, a British 3D computer-animated comedy film featuring Postman Pat, star of a long-running BBC children's series.