Aloisi Masella was created Cardinal-Priest of Santa Maria in Vallicella by Pope Pius XII in the consistory of 18 February 1946. He was promoted to Cardinal Bishop of Palestrina on 21 June 1948. On 27 October 1954, Pius XII appointed him archpriest of the Basilica of St. John Lateran and prefect of Sacred Congregation for the Discipline of the Sacraments. He was chosen chamberlain of the Roman Church (or camerlengo) on 9 October 1958 by the Curial cardinals, as the late Pius XII had yet to appoint anyone to that post, for the conclave of that same year.