Validio Mantovani was born in Ariano Polesine in Veneto on 20 October 1914 into socialist family. After the rise of the fascist movement the family was faced with intimidation and violence. In 1924 the Mantovani family moved to Milan. Validio found a job in the Pirelli Sapsa factory and came into contact with the communist party which was popular in the industrial regions of northern Italy.  

After the German occupation of northern Italy in 1943 Validio became an important member of the Gruppi di Azione Patriottica (Patriotic Action Groups: GAP). The GAP carried out risky tasks such as attacks on enemy units and headquarters, and assassinations of German and Italian Social Republic officers, fascist leaders or spies.  

One of the first actions Validio took part in was an unsuccessful assassination attempt on Gino Gatti on 20 October 1943. Gatti was a captain of the Guardia Nazionale Repubblicana (Republican National Guard) and had a reputation for torturing partisans. Validio was then promoted to command the Gramsci detachment, a smaller group within the GAP, and took part in numerous actions in Milan, including the successful assassination attempt on Aldo Resega, a Milanese fascist official on 17 December 1943. Because of his actions, Validio was transferred to Genoa to serve as the deputy commander of the local GAP.  

On 26 July 1944 Validio was captured because of his alleged participation in a series of attacks in Genoa. He was sent to the San Vittore prison in Milan where his father, Rottilio, was also being held for his involvement with the resistance. On 31 July 1944, Validio, Rottilio and four other partisans, including a seventeen-year-old boy, were executed near Milan. In total, seven members of the Mantovani family were executed for their involvement with the resistance.