Berger had achieved the rank of "Major der Reserve" in the Wehrmacht by 1938, but his initial rank upon joining the "Allgemeine-SS" was "SS-Standartenführer", based upon his SA service. Berger played a key role in directing the fifth column "Sudetendeutsches Freikorps" during the Sudeten Crisis in Czechoslovakia in 1938, and the organisational skills he displayed there marked him as highly suitable for the SS recruiting role.