His overall goal was to work collaboratively and to trespass conventional boundaries. He resented the idea of an isolated artistic genius and his entire production can be seen as a subsequent and vibrant example of praxis in a constant flux. He believed in the need to trespass conventional boundaries between artistic disciplines. This is visible from his engagement in Fluxus, over numerous collaborative performances to his position as a professor at the Art Academy in Hamburg (Hochschule für Bildende Künste - HfBK).
Christiansen lived almost 40 years on the Danish Island Møn. He presented a retrospective exhibition in Copenhagen and participated in the music festival Wundergrund shortly before his death.