His father Cesare Fiorio was a former racer, the head of Lancia's factory WRC team and sporting director for Scuderia Ferrari.

Fiorio began his World Rally Championship career in 1986, competing for the Jolly Club team in five WRC events in a Fiat Uno Turbo.

He lost control of his Delta Integrale on the fifth stage, and crashed into the crowd at about 145 km/h (90 mph), killing two spectators – Swedish rally driver Lars-Erik Torph and his co-driver Bertil-Rune Rehnfeldt – and injuring three others.

In 1994, Fiorio competed in only two WRC events, retiring with a Ford Escort RS Cosworth in Portugal and taking fourth place with a Delta HF Integrale at the Acropolis Rally.

[1] After making a comeback to the WRC by competing at his home event in 2000 and 2001, Fiorio went on to do a full Production World Rally Championship programme for the Ralliart Italia team in 2002.

He took his Mitsubishi Lancer Evolution 7 to production car class victory at the Rally Finland, and finished fifth in the PWRC drivers' championship.