Despite the fact that his brother Joseph was a bishop of the Ukrainian Autocephalous Orthodox Church in 1920s and the Nazi Germany collaborator during occupation of Kyiv, following the World War II Mykhailo Oksiyuk made an excellent career as a religious functionary.

[1] Born as Mykhailo Oksiyuk in Łukowisko, Siedlce Governorate (part of Russian Empire) on 29 September 1884 in a rich peasant family,[2] in 1897-1901 he studied at the Warsaw Theological School.

Following the invasion of Nazi Germany of the Soviet Union, Oksiyuk stayed in Kyiv and in 1941-1942 for short time returned to his work in the library of the Ukrainian Academy of Sciences.

During that time he also worked at the Kyiv city administration department of culture and education as an instructor of religious dominations section.

In April 1945 the Russian Orthodox Church Holy Synod appointed protoiereus Mykhailo Oksiyuk a bishop of Lvov-Ternopol.

His arrival to Lviv coincided with detention of Metropolitan of Galicia Joseph (Slipyj) and start of the Soviet campaign of liquidation of the Ukrainian Greek Catholic Church through a union.