On August 5, 1914, together with a group of riflemen, Kula came to Kraków where he was named commandant of the 4th Company of a group of Mieczyslaw Trojanowski. In the fall of that year, Kula took part in the First Cadre Company's fighting against Russians in the area of Kielce. On October 9, 1914, he was promoted to the rank of Podporucznik (second lieutenant), by Józef Piłsudski and Kazimierz Sosnkowski. 18-year-old Leopold then fought in the battles of Krzywoploty and Łowczówek (November – December 1914). He was generally regarded as an excellent and courageous leader.