Gimpel was a seasoned operative, having begun activities as an intelligence informant in the mid 1930s in Lima, Peru where, while working for Telefunken as a radio engineer, he transmitted shipping information to German U-Boats waiting offshore. He also conveyed information helpful to the German government gathered from corrupt Peruvian officials and underworld contacts. He was deported from Peru back to Germany in 1942, and was shortly recruited by the German Foreign Intelligence Service Amt VI. His experience as a covert operative and skilled radio operator was considered valuable, and he was reportedly assigned to serve in Operation Pelikan, a German espionage mission designed to cripple the Panama Canal which was cancelled shortly before it was scheduled to take place.