Cologna is a native Rumantsch speaker. In 2006, Dario Cologna won a bronze medal at the 10 km classic event in the Junior World Championships in Kranj, Slovenia. Cologna debuted in the FIS Cross-Country World Cup in Kuusamo in November 2006, and took his first points in Falun in March 2007. During the 2007–08 season, Cologna finished in the top ten four times and placed 37th overall.