Theiler grew up in the Ruhr area of Germany, until in 2001 when he went to study at the German Musical Academy in Osnabrück . With his diploma as a state-approved stage and musical actor he graduated in August 2004 from his theatrical studies (singing (tenor), dancing and acting). During his training he worked in various productions on stage, including at the opera house in Osnabrück and in the Aalto Theater Essen.