At age 14, William Skylstad left home to attend seminary, and was trained for the priesthood at Pontifical College Josephinum in Worthington, Ohio. Twelve years later, he was ordained a priest of the Diocese of Spokane on May 21, 1960. Father Skylstad went on to attend Washington State University and serve as an assistant pastor in Pullman, Washington. After that, he was principal of a minor seminary (a type of seminary preparatory high school for boys) in Colbert near Spokane, evaluating student fitness for the priesthood. He also served as pastor of St. Joseph Parish in Colbert, and sat on a personnel board that counseled the bishop on problem priests. In the summer of 1974 Skylstad became pastor at Assumption of the Blessed Virgin Mary parish, Spokane. In 1976 he was made chancellor of the diocese.