Pietro began attending the New Alexandria School of Enlightenment in 1988, followed by his brother Marco two years later. There, he met his best friend, Rawya Zaghloul and found out that his childhood friend and neighbour, Clemente Alborosie, was a wizard. Like his father, Pietro excelled in Defence, though also inherited his lack of interest in anything other than a few select classes. Throughout his years at the school, Pietro was known for his charismatic and confident personality as well as his legendary sexual endeavours which may or may not have included a professor or two. His wild popularity with nearly everybody in the school made him a prime candidate for the delegation to Beauxbatons Academy of Magic in order to compete in the Triwizard Tournament during the 1994/1995 school year.
In the summer of 1994, Pietro served as a junior Auror under his father during the 1994 Quidditch World Cup. It was there where he was introduced to Nymphadora Tonks, a bubbly, free-spirited British Auror who became his partner for the duration of the tournament. The two got on quite well, with the two developing mutual feelings for each other; however, after the tournament ended, Pietro's education and Tonks' Auror duties kept them apart. The same year, Pietro traveled to Beauxbatons Academy in France where he partook in the Triwizard Tournament against Aimee Lévesque and Viktor Krum, the Beauxbatons and Durmstrang champions respectively. Pietro dominated most of the tasks, beginning with the Sword Duel against the other champions, which he won while wielding the legendary Sword of Alexandria, and ending with the Maze Run.
After winning the Triwizard Tournament and graduating from New Alexandria, Pietro accepted a post in the Italian Ministry of Magic's Auror department granted to him by the Minister for Magic. Pietro reconnected with Tonks, with the two beginning a relationship in the summer of 1995; they became engaged shortly thereafter, and because of a surprise pregnancy, the two married in April 1996. Their first child, Carmine Angelo De Santa, was born on 23 November 1996, followed by a daughter; Alessia Andromeda De Santa on 7 June 2001.