As a former swimmer, Gianni – born in Rome in 1966 – competed in three consecutive Olympics (1984, 1988, 1992). He won a silver medal in the 100m breaststroke at the 1986 World Championships in Madrid and a bronze medal in the same event at the 1991 World Championships in Perth. He also won a total of five bronze medals at European Championships (100m breaststroke: Strasbourg 1987, Athens 1991; 4x100m medley: Sofia 1985, Bonn 1989; 50m breaststroke: Gelsenkirchen 1991 Short Course).
After finishing his career as an athlete, in 1994 he joined Procter & Gamble where he held Domestic, Regional and Global roles on various product categories. He was the Associate Director of the organising committee of the 2009 FINA World Championships held in Rome. He has been with LEN since November 2015.