In 1894 he was promoted to Major and he took a two-year service to the description of the country office of the General Staff in Vienna and in the military history department of the war archive.

Kusmanek was ennobled by Emperor Franz Joseph I on October 3, 1913 and, in memory of his former training center, the Theresian Military Academy in the castle in Wiener Neustadt, chose the predicate "from Burgneustädten".

The Austro-Hungarian army had to retreat west after the summer campaign of 1914, but held on the Przemyśl fortress, that was besieged by Russian troops.

After the fall of the northern defence line and a last, failed, very costly attempt to break out on March 19, the general decided to hand over the fortress to the Russian besieging army.

Upon the Eastern front armistice of 1918, he returned to Vienna and was received by Emperor Charles who decorated him with the Order of the Iron Crown 1st Class and appointed Colonel General on March 1, 1918 (with the rank of May 15, 1917 ).