Pietro Pistis was born in Lanusei (NU) on 18 April 1916, the son of Bernardo and Filomena Usai. Called up for military service, he served as a sergeant in the Engineer Corps during WWII.

On 8 September 1943, the day the Armistice between the Kingdom of Italy and the Anglo-American forces was announced, he was stationed in Viareggio where, as a straggling soldier, he came into contact with the first units of the Resistance movement that were forming in the area. He was arrested by the Republican National Guard and sent to carry out forced labour on the Gothic Line on behalf of the Todt Organisation. He managed to escape and join the 'Baroni' resistance formation, active in Lucca and the Serchio Valley, where he was appointed head of a Sardinian partisan unit. The team used to carry out sabotage actions, weapons collection, intelligence service. In June 1944, they chose one of the last tunnels between Ponte a Moriano and Borgo a Mozzano to sabotage the Lucca-Aulla railway line, in order to slow down German war operations: the partisans aimed to destroy the bridge at the tunnel exit. Pistis was leading the group in the darkness of the night when they realised that there were sentries on guard. They decided to continue the operation, but the German soldiers noticed them and opened fire: Pistis, being ahead of the others, was killed instantly while his companions managed to escape. The recognition cards as a partisan indicate him as having fallen on 25 September 1944.

On 18 October 1992, a memorial stone in his honour was placed in Borgo a Mozzano by the town council and the Combatant and Patriotic Associations in an open space on the edge of Via Ludovica (Provincial Road 20), near an anti-tank wall built by the Germans in the 'Madonnina di Mao' area. The memorial stone consists of a large irregular block of marble cut crosswise on which the epigraph is engraved. It is commemorated every year by the town council, the ANPI and local associations. In Lanusei (NU) a town street was named after him.