On February 7, 1966, Ryan was appointed the first archbishop of the Archdiocese of Anchorage, Alaska, by Pope Paul VI. He received his episcopal consecration on the following March 25 from Cardinal Francis Spellman, with Bishops Edward Joseph Maginn and Edward Ernest Swanstrom serving as co-consecrators. The Anchorage Archdiocese was erected following the 1964 Good Friday earthquake, and was formed from the South Central area of the Diocese of Juneau. After nine years in Alaska, Ryan was named Coadjutor Archbishop for the Military Vicariate and Titular Archbishop of "Gabii" on November 4, 1975.