Bielefeldt completed his abitur in 1976 in Gymnasium Eppendorf in Hamburg, before studying sociology and psychology at the University of Hamburg, financing his studies by working for a company which refurbished apartments, but not completing the course.
Bielefeldt then took an acting course with Philippe Gaulier in Paris, and participated in various street theatre groups, where he developed the character Herr Holm. In 1991, Bielefeldt debuted in the cabaret production Herr Holm – Keiner für alle. The series only ran for a short time, but excerpts from it are still broadcast, adding to the popularity of Bielefeldt and Herr Holm.
Bielefeldt also appeared in multiple stage productions, and in 2006 he appeared as a policeman in the film 7 Zwerge – Der Wald ist nicht genug.
Herr Holm"s given name is Klaus-Dieter, but he is almost always referred to as Herr Holm. Since 2009, Bielefeldt plays Herr Holm as a foreman instead of as a policeman in Vorsicht Baustelle!.
