[1] He would remain in the Italian air force after World War I, rising through squadron commands to head up the Castiglione Fighter School.

As World War I began, he volunteered for military service in the engineers.

After a transfer to the Corpo Aeronautico Militare, he earned a pilot's license on 13 March 1916.

On 28 July 1916, he completed a bombing sortie despite constant attacks by a pair of enemy fighters; he was awarded a Silver Medal for Military Valor for this feat.

[2] On 16 February 1917, he brought back his flaming Voisin to a landing at Monfalcone; he received a bronze medal for Military Valor for saving the craft and himself.

His diligence was rewarded with a second silver medal for Military Valor, received 15 August 1918.

[2] On 1 February 1919, the Bongiovanni military intelligence commission credited Mario Fucini with seven confirmed aerial victories.