His real surname was actually "Valensi", but was accidentally mistaken as "Valenzi" by an employee of the town hall of Naples in 1944.

In November 1941, Valenzi was arrested and tortured with electricity: he resisted interrogation and was sentenced to life imprisonment and forced labor by the Fascist regime of Vichy and interned for a year in Algeria.

He was freed by the Allies in March 1943 and was sent by the PCI to Naples, in order to prepare the arrival of Palmiro Togliatti from the Soviet Union.

After the end of the war, Valenzi was elected Senator with the PCI and held his seat from 1953 to 1968.

He died in Acerra, in the "Villa dei Fiori" clinic, where he was hospitalized for days, on 23 June 2009, a few months before his 100th birthday.