Sigbert Heister was already adept at warfare since his youth because his father Gottfried Heister was vice-president of the court war council of the Holy Roman Empire. He showed to be a capable and brave soldier early on. He participated in the defense of Wien in 1683 after which he took to lead to the Balkan campaign in 1689 when he freed Batočina and Niš in Serbia. At Senta in 1697 he led the right wing of the Austrian army. Later he was accounted to defend Wien from Rakoczi’s rebels. Finally, he took part in the capturing of Belgrade in 1717. On account of his great military success and contributions to the military effort of the Holy Roman Empire, Sigbert Heister received the title of a count and a palace in his birth town – Kirchberg an der Raab.