Father Leies was born in Chicago on April 24, 1926, the son of Alexander and Thecla (Eggar) Leies. He had two sisters, Marie (Perry) and Carol (Ferrari), both deceased, and a brother who died at a young age. Two of his uncles, Brother Herbert Leies and Father John G. Leies, were Marianists.

It was at St. Michael High School in Chicago where he had daily interaction with Marianists. There, he came to admire Marianists including Brothers Ed Goerdt, Gene Feld and Ed Dunne and desired to follow their way of life. In 1943, he entered the novitiate in Galesville, Wisconsin. Father Leies made first vows on Aug. 15, 1944, and perpetual vows on July 15, 1948, both at Marynook in Galesville. He was ordained to the priesthood on July 22, 1956, in Fribourg, Switzerland.

Father Leies received a bachelor’s degree in education from the University of Dayton in Ohio in 1947. As part of his priestly formation, he earned a bachelor of sacred theology in 1954, a licentiate in sacred theology in 1956 and a doctorate of sacred theology in 1958, all from the University of Fribourg, Switzerland.

Before entering the seminary in 1952, he was a teacher at Don Bosco High School in Milwaukee from 1947-52. After completing seminary studies in 1958, he returned to Don Bosco as a chaplain and teacher until 1961, then served the former St. Louis Province as assistant for religious life until 1964. He then traveled to Lima, Peru, to serve as administrator of Colegio San Maria for four years. In 1968, he returned to the U.S. with the ministry at Chaminade College Preparatory High School in St. Louis, where he was a teacher and school chaplain for six years. In 1974, he was assigned to St. Mary’s University in San Antonio, where he ministered for the rest of his life. He served as professor, chaplain, chair of the theology department, administrative vice-president and president of the University. In 2007, he began his semi-retirement, always willing to help in any way possible. His long and distinguished service at St. Mary’s was recognized with the conferral of the title president-emeritus in 2017.