In 1905, Ricciotti entered the novitiate of the Roman Catholic religious order of the Canons Regular of the Lateran. After his seminary studies and completing mandatory military service, he was ordained as a priest in 1913. After ordination, Ricciotti continued his studies at the University of Rome, where he took courses in both philosophy and theology. At the same time he did coursework at the Pontifical Biblical Institute.

During World War I he was required to interrupt his studies and to perform military service, during which time he served as a military chaplain and volunteering for service at the front lines. Because of this experience, he came to oppose any kind of war.
During World War II, due to his office he was able to give refuge to many refugees at the congregation’s motherhouse at the Basilica of St. Peter in Chains. 

Ricciotti’s first important work is Storia d’Israele (English: History of Israel), published in 1932, where he supported the need to apply the Higher criticism to the study of the Bible, to be based on the original texts and not on the Latin Vulgate. In 1934 Ricciotti took a stand against the increasing antisemitism publishing the translations in Italian of sermons of Cardinal Michael von Faulhaber in favour of the Hebrews.

Giuseppe Ricciotti died in Rome on 22 January 1964.