Longo won his first national medal at the Italian Championships in 1990 with the bronze medal. On February 28, 1992 he made his debut in the Nordic Combined World Cup in Lahti . There he immediately reached 4th place. At the Nordic World Ski Championships in 1993 he reached 6th place in the Nordic Combined team competition together with Simone Pinzani and Andrea Cecon . In 1994 he won silver at the Italian championships. Shortly thereafter, Longo started at the 1994 Winter Olympics in Lillehammer . There he reached 44th place in the individual and 11th place in the team competition. In 1995 he won his first national championship title. From 1995 Longo also started in the cross-country skiing world cup . In 1996, in addition to the Italian championship title in Nordic combined, he also won the silver medal at the Italian championships in ski jumping. Shortly afterwards, he finished the 1995/96 World Cup season in combination in 15th place overall. This was the highest ranking he could achieve. In 1997 he again won gold in combination at the Italian championships. At the 1998 Winter Olympics in Nagano , he competed in the individual competition with the combined athletes and ended up in 22nd place. In the same year he won silver at the Italian Championships. From 1999 to 2003 he was then unbeaten Italian champion. In 2000, he also won the gold medal at the Italian Ski Jumping Championships.