2008-09: Filip Forsberg played for the Leksand organization's U-16 and J-18 squads over the course of the season. In 15 games for the J-18 squad, Forsberg scored 12 goals and added 9 assists for 21 points. In 8 games for the U-16 team, Forsberg scored 13 goals and added 4 assists for 17 points. Forsberg also played for Dalarna in the Rikspucken, scoring 4 goals and adding 3 assists for 7 points in 9 games for that league's champion.
2009-10: Forsberg spent most of the season with Leksand's J-18 squad, playing in 31 games for that squad. He scored 21 goals and added 16 assists for 37 points. In 4 playoff games, he scored 5 goals and added 3 assists for 8 points.
2010-11: Forsberg played for Leksand's J-20 squad, playing in 36 games in the SuperElite league. He scored 21 goals and added 19 assists for 40 points. Forsberg played for Sweden at the 2011 U-18 World Junior Championship, scoring 4 goals and adding 2 assists for 6 points in 6 games for the silver medalists.
2011-12: Forsberg skated in 43 games for Leksand in his first full AllSvenskan season and represented Sweden in both the U20 and U18 World Junior Championships. He scored 8 goals with 9 assists and was plus-3 with 33 penalty minutes as Leksand finished second in the regular season. In the ten-game, six-team qualifying series he scored two goals with one assist and was minus-two as Leksand finished fourth – failing to gain elevation to the Elitserien. Forsberg skated in all six games for gold medal-winning Sweden at the 2012 U20 WJC in January and was minus-1, finishing with an assist and 2 penalty minutes. As a captain for the silver-medal winning U18 squad he led the team with five goals and had two assists in six games. Forsberg was ranked first among European skaters by Central Scouting heading into the 2012 NHL Draft. Forsberg was chosen by the Washington Capitals in the first round, 11th overall, of the 2012 NHL Draft, and signed a pro contract with the Capitals in the summer of 2012.
Forsberg was dealt by the Washington Capitals to the Nashville Predators at the 2013 NHL trade deadline in the deal that sent Martin Erat to the Capitals.