Named Protonotary Apostolic on 27 June 1921, Caccia-Dominioni was raised to the rank of Monsignor on 24 September 1914. He was appointed Prefect of the Pontifical Household, the papalmajordomo, by Pope Benedict XV on 16 June 1921. Upon the death of Pope Benedict on 22 January 1922, Caccia-Dominioni and all other major Vatican officials, in accord with custom, automatically lost their positions during the sede vacante. He was later confirmed as Prefect of the Pontifical Household by Pope Pius XI on the following 7 February and succeeded to the post of Canon of St. Peter's Basilica on 14 February 1924. Caccia-Dominioni was considered to be a protege of Pius XI,[2] at whose final hours the former was present in his bedchamber.[3]
According to David Kertzer, Caccia-Dominioni was a pederast.[4] The OVRA had a file on him, which detailed that he often lured young boys to his apartment in Rome for sex, and that the pope had been aware of this.[5]