 In addition to his cinematic work, he played a diversity of different roles on stage.Koch portrayed amongst other Peer Gynt and Leonce in "Leonce and Lena" at the municipal theatre of Darmstadt.At the Schiller theatre in Berlin he played the character Roller in Schiller's "The Robbers" and Orest in Goethe's "Iphigenie auf Tauris".