The actor Kurt Middendorf first finished an education as a bookseller before he dedicated to the acting. As a trained actor and singer he made his stage debut at the theater in Barmen in 1905. Afterwards followed engagements in Hamburg, Zürich and Dortmund among others.
With the outbreak of World War I Kurt Middendorf served in the army. He was only able to continue his stage career after the war, this time in Berlin.
In Berlin he joined the film business and already in his first year he impersonated numerous roles in front of the camera. To these works belong "Margot de Plaisance" (19), "Ut mine stromtid" (19), "Lilli" (19), "Verlorene Töchter" (19) and "Retter der Menschheit" (19).
At the beginning of the 20s followed again many engagements for movies and he took part in the silent movies "Das rote Plakat" (20), "Das Mädchena aus der Ackerstrasse" (20), "Lepain, der König der Verbrecher" (20), "Der Kurier von Lissabon" (21), "Louise de Lavallière" (22) and "Der Seeteufel"(23).
In the sound film era of the 30s he only got offered smallest roles and was no longer mentioned in the credits like "Abschiedswalzer" (34).