In the summer of 1914, Konovalets was mobilized into the Austro-Hungarian Army and during the First World War rose to the rank of a second lieutenant serving in the 19th Regiment of the Lviv Regional Defense. In 1915 he was taken prisoner of war by the Russians during the battles near the mountain Makivka (Carpathian Mountains) and interned in a POW camp near Tsaritsyn, Chornyi Yar. In 1916 he was transferred into the concentration camp near Dubovka. While in captivity he joined a group of former Galician officers (such as Andrii Melnyk, Roman Sushko, and Fed Chernyk among others) who fled to Kyiv together. In November 1917, together with the Galician-Bucovina Committee, he organized the Halytsko-Bukovynsky Kurin of the Sich Riflemen as part of the Doroshenko Regiment. Two months later he assumed its command and helped suppress the Communist uprising in Kyiv as well as resisting the Antonov-Ovseenko offensive. In March 1918 his riflemen, together with the Zaporizhia Corps of the Ukrainian People's Republic and the reformed Haydamaky Kish of the Sloboda Ukraine, liberated Kyiv from the Soviets. In May 1918 his military unit was disbanded due to its political views.