Teofil Kostruba was born on 26 May 1907 in Stara Yahilnytsia, now Nahirianka rural hromada of the Chortkiv Raion of the Ternopil Oblast in Ukraine.

[1][2][3] Due to a serious illness, he was forced to leave his studies at the Chortkiv Gymnasium, but during 1924–1928 Kostruba was engaged in self-education and was active in public life.

In 1939, he graduated from the Philosophical and Theological Faculty of Lviv University (Kostruba's master's thesis was dedicated to the charters of Prince Lev).

[1][2][3] In 1940, Metropolitan Andrei Sheptytskyi secretly ordained Kostruba a priest, who from then on lived in the monastery of St. Onufriy in Lviv.

At the same time, Kostruba collaborated with the editors of Catholic publications, including the magazines "Postup" and "Khliborobskyi Shliakh" and the newspaper "Nova Zoria", as well as co-publisher of the almanac "Za Velych Natsii", editor of several issues of "Literaturna Skarbnytsia", "Dobra Knyzhka" (Lviv), and "Ukrainska Knyzhka" (Zhovkva).