In March 2012 Paltrinieri won the Italian 800 metres freestyle title, and two months later, he left everyone in his wake at the European Championships in Debrecen, defeating renowned Hungarians Gergő Kis and Gergely Gyurta in the 1500 m. His time of 14:48.92 qualified him for the Olympics and, at the time, was the year's second-fastest 1500 m swim, breaking the championship record. He is trained by Stefano Morini. At 2012 Summer Olympics, the 17-year-old Italian advanced to his first Olympic final with the 4th fastest time of 14:50.11. In the final he finished 5th in 14:51.92.