As a seminarian, he established and organized the Catholic Students' Mission Crusade to aid missionaries in foreign countries.

[2] He then furthered his studies at the Pontifical University of St. Thomas Aquinas in Rome, and toured American missionary outposts in Asia.

[1] Upon his return to Ohio, Thill served as professor of oratory at Mount St. Mary's, and became chancellor of the archdiocese (1935) and domestic prelate (1937).

[1] Despite the lingering effects of the Great Depression, Thill managed to liquidate the diocesan debt of nearly $250,000 in late 1942.

[1] On December 23, 1944, Pope Pius XII moved the episcopal see from Concordia to Salina, Kansas,[3] much to the chagrin of local Catholics.