In 1910 he defended his dissertation on the Swedish campaign in Ukraine 1708-1709 and year later became a professor of a military history.

In 1914 Yunakiv was pressured to resign after his implementation of teaching reforms found no support in the academy.

In August 1919 he was appointed as a chief of joint staff for both the Ukrainian armies during the counter advance onto Kiev and Odessa.

On 10 October 1919 Yunakiv was promoted to Major General and during the following year briefly served as minister of defense and as head of the Supreme Military Council of Ukraine.

Later he emigrated to Poland where he was a member of the Ukrainian Military History Society and the editorial collective of Za derzhavnist’.