Born in Rechytsa, Byelorussian Soviet Socialist Republic, Kiryienka won his first national time trial championship in 2002. His early career focused mainly on the track, where he won the Points Race at the 2008 UCI Track Cycling World Championships. Later that season Kiryienka won Stage 19 of the Giro d'Italia, a mountainous affair leading to Presolana, after spending the day on the attack and registering more than 6 hours and a half in the saddle. He attacked his six breakaway companions at the foot of the Monte Para climb and soloed to the finish for the win, by a margin of over four minutes.