In 1915, Cavallero was transferred to the Italian Supreme Command. A brilliant organizer and tactician, Cavallero became a Brigadier General and Chief of the Operations Office of the Italian Supreme Command in 1918. In this capacity, Cavallero was instrumental in forming plans that led to Italian victories at Piave and Vittorio Veneto during World War I. During his time as chief of the plan of Italian General Staff, he developed an antipathy with Pietro Badoglio, the "Sottocapo di Stato Maggiore" ( vice chief of the staff ) of the army.