In 1819 he became Cardinal Protoprete (Protopriest) and consequently opted for the titulus of San Lorenzo in Lucina, that two centuries earlier had belonged to his forebear and namesake Giulio Gabrielli the Elder (1604–1677). In 1820 he resigned from Prefect of the Congregation of the Council and was appointed Pro-Datary of His Holiness.
In 1819 he took on the role of Cardinal Protopriest (Protopriest) and subsequently adopted the title of San Lorenzo in Lucina, a position previously held by his ancestor Giulio Gabrielli the Elder two centuries prior. In 1820, he stepped down as Prefect of the Congregation of the Council and was appointed Pro-Datary to the Holy See.