In the First World War Shandruk was the commander of the 3rd Battalion of the 232nd Reserve Infantry Regiment of the Russian Imperial Army.

Until 1936, he worked in different positions for the Ukrainian National Republic government in exile initially led by Symon Petliura.

In 1936 he joined the Polish Army, after which he obtained further training in the Wyższa Szkoła Wojenna (Higher Military Academy).

After capitulation, Shandruk, as a Polish officer, was captured and sent to a German POW Camp, from where he was later released due to his injuries.

After that, he requested a meeting with the Polish general Władysław Anders in London, and asked him to protect the army from deportation to the Soviet Union.

Shandruk penned a number of works regarding military history in Ukrainian, Polish, and English, among them Arms of Valor (NY, 1959).