A bank employee by profession, Forster was made Gauleiter of Danzig in October 1930, reorganizing the disrupted Nazi Party in the free city.
He also became head of the shop assistants’ group which had been integrated into the German Labour Front. Forster gradually took control of government policy in Danzig Free State, being made Reich Regent there just before World War II, after having directed clandestine and open preparations for its seizure by the Germans.
An SS Lieutenant-General, Forster had a black record of atrocities against the Poles, who sentenced him to death in May 1948 after he had been extradited there the previous year to stand trial. The sentence of the Danzig court was subsequently commuted to life imprisonment.