To prepare for the priesthood, Aloysius Knier attended the parochial school at School Hill, Wisconsin, under the direction of Salvatorian Sisters and the pastor, a member of the Society of the Divine Savior of Saint Nazianz. He then attended the Salvatorian Seminary at Saint Nazianz, Missouri, for six years, and then spent two years in the study of philosophy at Saint John’s College in Collegeville, Minnesota. He then attended La Valle University at Quebec, Canada, to study theology for four years. He was ordained a Catholic Priest on April 25, 1942, and celebrated his first Mass at Holy Trinity Catholic Church in School Hill. He was commissioned a U.S. Army chaplain during World War II, continuing in service through the Korean War, and retired from the military after 20 years of military ministry. He then served the church in the Green Bay, Wisconsin Diocese.