Gangl was promoted to Oberfeldwebel in November 1938. From October 1939 he was supposed to study at an officer school of the Wehrmacht. However, his regiment needed to be stationed in the Saar-Palatinate on the border with France, in preparations for war. There, on September 7, 1939, eleven French divisions, 25 km wide, crossed the border and advanced about 8 km into German territory. Though, they withdrew within two weeks on orders from Gamelin. This was Gangl's first moment of combat in the second World War. Gangl spent six months in hospitals in the following months of the "Phoney War". He returned to his regiment on May 14, 1940, and took part in the western campaign. There he served as the commander of a reconnaissance unit of the 25th Infantry Division of the Wehrmacht. After the Armistice of Compiègne, he was instructor in the artillery replacement department 25. After a short home leave in August 1940, he was an instructor at a base in Taus in the Protectorate of Bohemia and Moravia. He began a one-month training at the artillery school in Jüterbog on November 25, 1940.