On 26 June 1912 he took off from Verona with three of his friends, Nico Piccoli, Umberto Sanguinetti and Alberico Camporesi, on an aerostat named Libia; the four planned to fly to Budapest, but exhaustion and low temperatures forced them to land in the Hungarian town of Buek, on the border with Austria.

Having later become an artillery sergeant major, he was wounded on Mount Podgora, near Gorizia, during the Third Battle of the Isonzo and was awarded the Silver Medal of Military Valor.

He was however harshly critical of the Italian colonial policy in Somalia, which imposed a regime of forced labour on the native population, presenting it as a "work contract" in the reports and relations of governors and the speeches of ministers.

In one of the many reports he wrote to Mussolini between 1931 and 1933 he wrote:[6][8][9][10][11][12][13][14] The forced labour which for some years has been imposed on the natives of Somalia, to no avail cynically disguised in 1929 with a contract of employment, is far worse than true slavery, as the indigenous worker has been stripped of the valid protection of the slave which was entailed by his venal value, protection that granted him at least the minimum of care that the lowliest of the carters has for his donkey, in the worry of having to buy another if it dies.

While in Somalia, when the native assigned to a concession dies or becomes unable to work, their replacement is immediately requested from the competent government office which provides it free of charge.

Due to his numerous public complaints about influential figures of the Fascist regime as well as his loyalty to Arpinati, who had meanwhile fallen out of favour, Serrazanetti soon antagonized then-secretary of the PNF Achille Starace, who forced him to return to Italy.

In the same month, a special commission sentenced Arpinati to five years of confinement, and a few days later the positions of his friends were also examined; among them Serrazanetti, Marcello Reggiani, Antonio Bedogni, Enrico Gelati and Giuseppe Vittorio Venturi were sentenced to five years of confinement in Sardinia, for "giving solidarity, displaying attitudes in stark contrast to the traditionally fascist spirit, to a party member eliminated from the ranks for having notoriously placed himself against the directives of the PNF".

[17][18][7] In June 1940, immediately after Italy entered into the Second World War, Serrazanetti enlisted in the Royal Corps of Colonial Troops, participating in the following month in the conquest of the Sudanese town of Kassala.