On 8 September 1983, he was appointed Titular Archbishop of "Volsinium", Pro-Librarian of the Holy Roman Church, and Pro-Archivist of the Holy Roman Church. Stickler received his episcopal consecration on the following 1 November from Pope John Paul II himself, with Archbishops Eduardo Martínez Somalo and Rosalio José Castillo Lara serving as co-consecrators, in the Sistine Chapel. He was created Cardinal-Deacon of San Giorgio in Velabro by John Paul II in the consistory of 25 May 1985, becoming full Librarian and Archivist two days later, on 27 May.