In his career he won 12 World Cup races (7 wins in giant slalom , 5 wins in slalom ) and was overall World Cup winner in 1973/74 . His first two victories in December 1972, the giant slalom in Val d'Isère and the slalom in Madonna di Campiglio, he achieved with the high starting numbers 45 and 42. This also makes him the youngest alpine athlete (as of January 1, 2017) World Cup winner in the men. At the 1976 Winter Olympics in Innsbruck , he won gold in slalom. At the 1974 World Cup in St. Moritz , he came third in the giant slalom. Four years later he reached second place in the slalom world championship in Garmisch-Partenkirchen . From 1974 to 1982 he won a total of ten Italian championship titles.
Piero Gros was involved in the organization of the 2006 Winter Olympics in Turin . He organized the volunteer program with around 20,000 volunteers. He was also mayor of his hometown Sauze d'Oulx from 1985 to 1990.