He won two medals in the K1 team event at the ICF Canoe Slalom World Championships with a gold in 2013 and a bronze in 2011. He also won a silver and a bronze medal at the European Championships. He won two World Cup races in the K1 class (Ivrea 2016 and Markkleeberg 2017). De Gennaro finished 7th in the K1 event at the 2016 Summer Olympics in Rio de Janeiro.