Campioni was promoted to "ammiraglio di squadra" ("squadron vice admiral," a rank equivalent to vice admiral) in 1936 and in 1938 he assumed the post of Deputy Chief of Staff of the Navy. Held in high regard as the most promising officer in the "Regia Marina", he became commander of the 1st Naval Squadron – the Italian main battlefleet – in 1939 with the battleship "Giulio Cesare" as his flagship. In the same year he became a Senator of the Kingdom of Italy.