In 1937 he became lieutenant and was given command of MAS boats; in June 1939, after becoming aide to Prince Eugenio of Savoy, he organized an expedition in the East African lowland, earning a commendation for his organizational capacity.

[1] In June 1940, with Italy's entry into World War II, Faggioni became a member of the 1st MAS Flotilla in La Spezia, where he was given command of a special section of MT explosive motorboats.

He was later tasked with organizing and training a group of eight (later reduced to six) MTM explosive motorboats that would attack British shipping in Souda Bay, Crete, under his command.

Carried by the destroyers Francesco Crispi and Quintino Sella till near Souda, the six MTM boats were led by Faggioni inside the bay, where they attacked different objectives.

In 1960 became a member of the High Council of the Armed Forces, and in January 1963 he was promoted to rear admiral and given command of the La Spezia Naval Base.