During his career he won six Olympic medals (all bronzes), and also the 50 km event at the Holmenkollen ski festival in 2000.

His biggest successes though were at the FIS Nordic World Ski Championships, where he earned a total of eight medals.

In 1998, he earned the Holmenkollen medal (shared with Fred Børre Lundberg, Larissa Lazutina, and Alexey Prokurorov).

During the 2001 FIS Nordic World Ski Championships in Lahti, he tested positive for use of the banned plasma expander Hemohes together with five fellow Finnish cross-country skiers.

[1] Presently Kirvesniemi works as the Plant Manager and Board Member at Yoko Ski.