Gazzera was born in Bene Vagienna, he joined the Italian Army and fought in the Italo-Turkish War and World War I. He was one of the signatories of the Armistice of Villa Giusti, which ended the war with Austria-Hungary on the Italian Front.
In 1928, starting as the Under-Secretary in the Ministry of War, Gazzera was the Minister of War from 1929 to 1933. From 1 August 1938 to 6 July 1941, Gazzera was the Governor of Galla-Sidamo in Italian East Africa.
General Gazzera commanded forces in the "Southern Sector" (the Galla and Sidamo area around Jimma) during the East African Campaign. Following the fall of Amba Alagi in May 1941, Gazzera succeeded Amedeo, Duke of Aosta as the acting Viceroy and Governor-General of Italian East Africa. After Jimma fell on 21 June, Gazzera staged a mobile defense and held out in Galla-Sidamo for several weeks. His forces finally capitulated in July 1941 when he was cut off by the Free Belgian Forces of Major-General Auguste-Éduard Gilliaert.
- Commanding Officer, Brigade Basilicata – 1926
- Commandant of War School – 1926
- General Officer Commanding, Division Genova – 1926 to 1928
- Under-Secretary Ministry of War – 1928 to 1929
- Minister of War – 1929 to 1933
- Governor of Galla and Sidamo – 1938 to 1941
- Member of the Commission for the Affairs of Italian Africa, Senate – 1939 to 1940
- General Officer Commanding, 24th Colonial Division – 1940 to 1941
- Acting Viceroy and Governor-General, Italian East Africa – 1941
- Prisoner of war – 1941 to 1943
- Commissioner for Prisoners of War – 1943 to 1945
- Time Magazine, Retort
Amedeo, 3rd Duke of Aosta
| (acting) Viceroy and Governor-General
of Italian East Africa
23 May – 6 July 1941