He graduated from the Armed Forces Staff College at Norfolk, Virginia, in 1965 and from the Air War College at Maxwell Air Force Base, Alabama, in 1968.Ryan became an aviation cadet in September 1949, and after completing pilot training at Reese Air Force Base, Texas, he was commissioned a second lieutenant in October 1950.

Ryan transferred to SAC headquarters at Offutt Air Force Base, Nebraska, in June 1962 as a staff officer in the Plans and Organizational Section of the Weapons Management Branch, Weapons Maintenance Division.

In February 1965 he entered the Armed Forces Staff College and following graduation in July 1965 he joined the SR-71 equipped 4200th Strategic Reconnaissance Wing at Beale Air Force Base, California, where he served as chief of the Quality Control Division and later as chief of the Maintenance Control Division.

Upon his return to the United States, Ryan served on the staff of the inspector general, Headquarters U.S. Air Force, Washington, D.C., from April 1970 to June 1971.

During 1972 and 1973, he completed a temporary tour of duty as commander, 303rd Consolidated Aircraft Maintenance Wing at Andersen Air Force Base, Guam, and participated in the Linebacker II campaign against North Vietnam in December 1972.

Ryan was promoted to general August 1, 1981, with date of rank July 31, 1981.