Kasper Pikkarainen was born in Helsinki, Finland. His father Ilkka was playing for Helsinki IFK at the time of his birth.
Pikkarainen played for TPS and in 2021-2022 while playing for the U16 team, he tallied 27 goals and 29 assists in 38 games. In 2022-2023 he played for TPS U-18 and scored nine goals and 15 assists in 39 games.
This past season, Pikkarainen played for the TPS Jr. team. He played in 34 games and recorded 12 goals and 16 assists. He was also selected to play for Team Finland in the WU18 tournament and scored one goal in five games.