[1] Gressle was ordained deacon on March 27, 1943, in Christ Church, Shaker Heights, Ohio, by Bishop Beverley Dandridge Tucker of Ohio and priest that September by the same bishop.
[2] That same year, on July 12, he married Marguerite Louise Kirkpatrick, with whom he had three children.
He was enthroned as sixth bishop of Bethlehem on December 4, 1971, and gained responsibility of the diocese on January 1, 1972.
[4] He was a member of the Executive Council of the Episcopal Church and was a trustee of St. Luke's Hospital, Bethlehem.
Between the 1970s and the 2020s, the diocese has been a major epicenter for clerical sexual abuse claims regarding priests, youth leaders, and organists, with multiple thousands of criminal charges against clergy and lay employees, including charges against Gressle ordinands.