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.

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.

Differently from Buonaiuti, his positions were finally judged not to be modernist, and he accepted criticism by the Pontifical Biblical Commission to some of his works.

His masterpiece is Vita di Gesù Cristo (English: Life of Jesus Christ), edited in 1941 and published many times.

The scholar Nicolotti writes: "His works on biblical texts, of a rather conservative character, show a solid historical and philological training, not at all alien to the contemporary acquisitions of the critic.

Giuseppe Ricciotti also wrote: La «Era dei martiri» (English: The Age of Martyrs), Rome, 1953, trans.

Ricciotti's book Vita di Gesù Cristo ("Life of Jesus Christ") was extremely popular and influential in Italy, selling 40.000 copies in its first edition and being praised by the Royal Academy of Italy; even Italian fascist dictator Benito Mussolini read a copy of the book.

Giulio Michelini OFM believes that Ricciotti's book shows many of the flaws of Catholic scholars of the time: a tendency towards gospel harmony, vehement and excessive attacks toward Protestant scholarship (especially Rudolf Bultmann), insufficient knowledge of Second Temple Judaism and even some anti-Jewish interpretation of the Gospels (see blood curse).

[19] Despite this, Ricciotti's work is still widely appreciated by Italian conservative Catholics like Vittorio Messori and Luca Doninelli.