2010-11: Niklas Hansson played 18 games with lower division club Jonstorps IF 's mens' team in southwest Sweden as a 16-year-old and played for Rogle in U18 Allsvenskan play. He also skated for Skane in the TV-Pucken tournament for high school players. Hansson had 2 assists and 2 penalty minutes with Jonstorps IF. He had no points or penalty minutes in five games with Rogle's U18 team. During the TV-Pucken tournament he had 5 assists with 2 penalty minutes in eight games.
2011-12: Hansson spent his first full season with the Rogle club – splitting the season between the U20 and U18 teams. He played in 18 regular season games and seven playoff contests in the SuperElit U20 league, finishing with an even plus/minus and scoring 2 goals with 3 assists and 6 penalty minutes. Hansson scored 3 goals with 28 assists and was +39 with 14 penalty minutes in 33 regular season games for the U18 squad. In five U18 playoff games he scored 1 goal with 3 assists and was +8. Hansson played three international games for Sweden's U17 team and had a pair of assists; finishing +5.
2012-13: Hansson made his pro debut with last-place Rogle IK in Sweden's Elitserien, skating in nine regular season games and six games during the Kval series relegation playoffs. He was -3 with no points and 4 penalty minutes in the regular season and had his first SEL point, an assist in the Kval series. Rogle was relegated to AllSvenskan, the Swedish second league; finishing fifth in the six-team tournament. Hanson played 41 games for the Rogle U20 team, including two playoff games, and scored 3 goals with 20 assists, finishing +23 with 47 penalty minutes. Hansson was ranked 26th amongst European skaters in Central Scouting's final rankings and was selected by Dallas in the third round (68th overall) of the 2013 NHL Draft.