 He made his religious profession on 11 May 1915.After completing his second year of theology (1916/17), Pirotta was chosen to continue his theological studies at Pontifical International Angelicum College in Rome, the future Pontifical University of Saint Thomas Aquinas, "Angelicum".In the meantime, he was ordained a priest by on 22 September 1917, at the St. John’s Co-Cathedral, Valletta, Malta.