After a period in karting, Colciago entered the Italian Formula Three Championship at the age of 19.

He spent the 2000 and 2001 seasons driving an Audi A4 in the European Super Touring Cup, in which he was a race winner on seven occasions.

His 2001 programme was dovetailed with a title-winning participation in the Swedish Touring Car Championship and he successfully defended this title in 2002.

In 2005, he was back in the ETCC in its new form as the World Touring Car Championship, driving a Honda Accord for independent entrant JAS Motorsport.

Then he made another return to Italy for a title-winning season in the Italian Touring Car Championship driving a SEAT.