 He developed a reputation for writing and performing short comic routines, which he performed in a strong Bavarian dialect, usually with his female partner, Liesl Karlstadt.Valentin also made numerous films, both silent and with audio; but it was as a stage performer in cabarets that Valentin built a reputation as one of the leading comic performers in Germany during the Weimar Republic.In 1923, Valentin appeared in a half-hour, slapstick film entitled "Mysteries of a Barbershop" ("Mysterien eines Friseursalons").