Ugo Mazzucchelli was the second of his parents' five sons, born into a large working-class family in Tuscany at Carrara, a prosperous midsized town, well known for the marble quarries in the surrounding hills and, among the politically engaged, as a long-standing hotbed of anarchism. Ariodante Mazzucchelli, his father, was a quarryman and a powerful influence throughout and beyond his childhood. After completing his basic schooling, Ugo Mazzucchelli was sent to work in the quarries nearby. Italy became inveigled in the war during 1915, and in 1917 Mazzucchelli's family sent the boy to help behind the frontline, where he joined a "youth team" deployed to bury the bodies of dead fighting men after the slaughter at Caporetto. This would have meant one mouth fewer for the family to feed and a few more lire for the family budget.