He took part as Rear-admiral in the Italo-Turkish War, commanding Italian cruisers in the Battle of Beirut. He twice served as Naval Chief of Staff during World War I and was reluctant to risk the Italian battlefleet in anything other than a major surface action. He favoured the action of smaller vessels, as the MAS which sunk the Austrian battleship Szent István. After the Italian rout at Caporetto he secured the coastal area. In the late days of the war he led the bombardment of Durazzo and the quick occupation of the coasts of Istria and Dalmatia.
After the war he was promoted to Grand Admiral (4 November 1924). He was ennobled by King Victor Emmanuel III and given the victory title of 1st Duca del Mare ("Duke of the Sea").
In 1917 he was named to the Italian Senate. In the October 1922 he was Minister of the Navy and chief advisor of King Victor Emmanuel III. He was President of the Italian Senate from 1943 to 1944 after the fall of fascist regime.