Originally developed by Theodor Emil Bergmann and a Mr. Müler in the early 1930s, the original prototypes were built in Denmark by Schultz & Larsen. After some refinement, the weapon entered domestic production under the designation MP34/I. Bergmann shared the production rights with Walther, as his own factory lacked the means to mass-produce the weapon at that time. In 1935, Bergmann began producing the weapon as the MP35/I, featuring minor detail improvements.
The MP34/I was bought in small quantities by Abyssinia, Poland, Sweden, and Bolivia, and the MP35/I was adopted by the German police. Denmark adopted the weapon as the BMK-32, produced under license by Junker & Ruh. During the Spanish Civil War, quantities of MP35s were sold to the Nationalist forces as part of Nazi Germany's support for Franco. In 1940, the SS ordered a large quantity of MP35s, which were marked with SS runes. Production ceased with Germany's defeat in 1945.
The MP35/I was a blowback-operated submachine gun that fired from a closed bolt. It utilized a patented two-stage trigger mechanism that allowed the user to fire single shots if the trigger was half-pulled and automatic fire if the trigger was fully depressed. Unusually, the magazine fed from the right side of the receiver; this proved somewhat awkward for reloading.