2009-10: Calle Andersson played for Malmo's U18 squad and skated for Skane in the TV-Pucken high school tournament. In 29 games he scored 1 goal with 2 assists and was plus-four with 34 penalty minutes. Malmo finished ninth in the ten team Allsvenskan South (U18) and did not make the playoffs. Andersson scored 1 goal with 1 assist and 2 penalty minutes in seven TV-Pucken games.
2010-11: Andersson played for Malmo's U20 team in the SuperElit league and also skated for the club's U18 team. He scored 2 goals with 4 assists and was plus-four with 20 penalty minutes as Malmo finished second in the South Division. In six games in Top 8 play he had no points and was minus-four with 4 penalty minutes. In 21 games with the U18 team he scored 2 goals with 5 assists and was minus-15 with 38 penalty minutes.
2011-12: Andersson moved from western to eastern Sweden, playing for Farjestads in the SuperElit (U20) league and represented Sweden at the 2012 U19 World Junior A Challenge and U18 World Junior Championship. Andersson put up big offensive numbers in his first year with Farjestads – scoring 12 goals with 24 assists in 49 games and was plus-five with 56 penalty minutes. In six playoff contests he scored 2 goals with 3 assists and was plus-one with 2 penalty minutes. He also played in 11 games for Farjestads U18 (including one playoff game) and scored 3 goals with 7 assists. In four games at the World Junior A Challenge he had 1 assist and 2 penalty minutes. In six games for Sweden's silver medal-winning team at the U18 WJC he had 3 assists and was an even plus/minus. Andersson was invited to the NHL Draft Combine and ranked 15th amongst European skaters in Central Scouting's final rankings prior to the 2012 NHL Draft.