Mozzoni was Cardinal Protodeacon from June 15, 1980 until he chose to become a Cardinal Priest, with the same titular church, on February 2, 1983.
Mozzoni je obnašao dužnost kardinala protođakona od 15. lipnja 1980. dok nije postao kardinal svećenik iste naslovne crkve, 2. veljače 1983. godine.