Born in Milan, Teruzzi completed military studies and was promoted colonel in the Italian Army at the unusual age of 28.

He later captured Nalut, and was wounded in the battle over Fezzan – being awarded the Silver Medal of Military Valor.

After service in World War I (when he was again decorated), Teruzzi took leave from the army in 1920, in order to engage in Fascist politics.

After the Fascist takeover, Teruzzi was elected to the Italian Chamber of Deputies in 1924 and gained successive terms.

After Mussolini's ousting and Italy's exit from the World War II Axis Powers – through the armistice in Cassibile at the end of July 1943, Teruzzi followed Il Duce in his Nazi-backed refuge in Northern Italy, and helped found the Fascist Italian Social Republic.