Born in Berlin, he was a trained carpenter and commercial artist.
The entertainer Harald Juhnke was one of the sponsors of the curly headed entertainer.
In 1959 Dahlen made his cinema debut in Kurt Meisel's comedy "Love forbidden - marriage allowed".
In 1964, Dahlen's career began in television.
The actor, also known in Switzerland and Austria, has appeared in more than 35 feature films.
He stood in front of the camera with Loni von Friedl, Elke Sommer, Claus Biederstaedt, Rolf Becker and Willy Millowitsch, among others.
Dahlen became known to a wide audience in 1978 in Michael Pfleghar's series "Klimbim".
Together with Ingrid Steeger and Iris Berben, Dahlen also played in the series "Two Heavenly Daughters".
In "A heart and a soul" he took over the role of the son-in-law of "Ekel Alfred" after Diether Krebs left.
He also took part in television series such as “The Commissioner”, “The Men from K3”, “Coast Guard” or “Tatort”.
Kirsten Kosinski (Anna Kristina) leaves her provincial town to work in the big city. After getting a job as a secretary, she finds herself occasionally "sellin her charms." Eventually, she becomes a full-time prostitute and feels the need to ensure the protection of a pimp to survive in this environment.
East Berlin, shortly after the construction of the Berlin Wall. Kurt Schröder and his family dig a tunnel to escape to West Berlin as they struggle to overcome the obstacles blocking their underground path to freedom.