Helm's career, however, though not long, consisted of more than lost or rejected roles. She was an inexperienced, untrained actress when Lang and his wife Thea von Harbou discovered her, but her vivid impression in "Metropolis" certainly suggested potential. In the years that followed, Helm would develop as an actress, and her credits have historical interest for the many talented if unjustly forgotten directors with whom she worked: Marcel L'Herbier ("L'Argent" 1927), Richard Oswald ("Alraune" 1930), Gustav Ucicky ("Im Geheimdienst" 1931), and Arthur Robison ("Furst Woronzeff" 1934), among others. She made several films with one of the most important directors of the period, G.W. Pabst, the most memorable being "The Loves of Jeanne Ney" (1927), in which Helm, not in the title role, gave a creepy performance as a blind woman. One of her best performances came in a typical role as a restless, aristocratic mistress of a wealthy military officer who falls for a poor soldier in Hanns Schwarz's superb, poignant but unsung masterwork, "The Wonderful Lie of Nina Petrovna" (1929).
Helm continued making films in Germany until the mid-30s. She also made one British film (Herbert Wilcox's "The Blue Danube" 1932) and also worked in France; some of her credits are French-language versions of her German films, sometimes shot simultaneously with them. During the waning days of the Weimar Republic, Helm refused to leave Germany to accept offers from Hollywood but she ultimately became dismayed by Nazi policies regarding the film industry and the hasty departure of much of Germany's best talent. Her career slipping, Helm retired abruptly after marrying an industrialist, sat out the war quietly in Italy and for the next 60 years remained an intriguing and elusive figure, her refusal of interviews nurturing the aloof persona which had briefly entranced so many.