After escorting to Libya the convoy that triggered the Battle of Calabria, Casardi became a protagonist, in July 1940, of the Battle of Cape Spada, in which Colleoni was sunk.[1][2] Following the loss of Colleoni, the 2nd Naval Division was dissolved; in August 1940 Casardi was placed in command of the 7th Naval Division, with flag on the light cruiser Eugenio Savoia and later on Emanuele Filiberto Duca d'Aosta.[1][2] For a year, as the commander of the 7th Division, Casardi participated in convoy escort, bombardment and minelaying missions; he was awarded the Silver Medal of Military Valor, the Knight's Cross of the Military Order of Savoy and Cross of the Order of the German Eagle, second class.[1]
Since August 1941, having left the command of the Seventh Division, Casardi was for two years the staff and general services director of the Regia Marina.[1] On 7 August 1943 he was appointed commander in chief of the Naples Naval Department.[1] Following the armistice of 8 September 1943, clashes broke out in Naples between Italian and German soldiers, and in a few days the city was occupied by German forces.[1][3] On September 11 Casardi, in order to avoid capture, sought refuge with his main collaborators in a building owned by his chief of staff, where he continued to work clandestinely until September 30, when German troops left Naples in the face of the insurrection of the population of the city and the Allied advance.[1][3] He immediately returned to his headquarters, devastated by bombing and fighting, and reactivated it on the following day, immediately starting the cooperation with the commands of the Allied forces, which reached Naples from 1 October.[1][3] He left the command of the Naples Naval Department in February 1945, and was then assigned to the General Secretariat of the Navy and later became president of the High Council of the Navy.[1]
In 1948 he was elected in the Italian Senate in the first legislature of the Italian Republic (1948–1953), serving as Undersecretary for Finance in the De Gasperi VI Cabinet.[4][1] He was placed in availability on 1 March 1949, and in the reserve on 1 January 1950, having reached the age limit.[1] Casardi died in Barletta on 11 January 1975.[1]