Born in Segni on 4 March 1881, Felici was ordained priest in 1903, he began his diplomatic career as a minor official at the Apostolic Nunciature to Serbia in Belgrade.
As a majority Serbian Orthodox Church at war with Catholic Austria relations were often tense.
He remained at the nunciature in Belgrade after the war when Serbia became part of the Kingdom of Yugoslavia.
In 1927 he was consecrated titular archbishop of Corinth and named Apostolic Nuncio to Chile.
Due to the military situation, he was recalled to the Vatican and spent the remainder of the war working in the Secretariat of State.