He was a member of the Union of Ukrainian Nationalist Youth [uk], and eventually became part of its executive council.

After Operation Barbarossa began, Lenkavskyi, by then known as a veteran of the Ukrainian nationalist movement, supported the Lviv pogroms, saying on 18 July 1941, "As for Jews, we are taking all measures leading to their extermination.

"[5] Lenkavskyi also co-wrote the Act of restoration of the Ukrainian state, and was arrested by the Gestapo for attempting to take control of an OUN publishing house in Kraków.

In this capacity, he focused on the history and ideology of Ukrainian nationalism, giving lectures to OUN members.

During his later years, he also developed an interest in Chinese and Indian philosophy, as well as the biographies of certain European philosophers such as Immanuel Kant, Arthur Schopenhauer, and Hryhorii Skovoroda.