2010-11: Sebastian Aho played for the Bjorkloven club in the northern Sweden town of Umea and represented Vasterbotten in the 2011 TV-Pucken high school tournament. He scored 3 goals with 6 assists and was -13 with 16 penalty minutes in 27 games for the club's U18 team and in three U16 games had 3 assists and 4 penalty minutes. Aho scored 1 goal with 3 assists and 6 penalty minutes in eight TV-Pucken tournament games as Vasterbotten captured a bronze medal.
2011-12: Aho went from Bjorkloven to Skelleftea and represented Sweden in international competion with the U16 team while again skating in the TV-Pucken tournament. He scored 4 goals with 14 assists and was +45 with 12 penalty minutes in 33 regular season games for Skelleftea's U18 team. Skelleftea was the runner up in the Allsvenskan playoffs and in seven games Aho had 2 assists and was +2 with 2 penalty minutes. A team captain for Sweden's U16 team he had 6 assists and was +7 with 4 penalty minutes in 11 games. Aho scored 3 goals with 8 assists and was +13 with 4 penalty minutes in eight TV-Pucken games as Vasterbotten captured a gold medal.
2012-13: Aho appeared in one Elitserien game with Skelleftea — spending most of the season with the club's U20 team in the SuperElit league — and represented Sweden at the U18 and U17 levels. He had no points or penalty minutes in his only Elitserien game. In 42 SuperElit games (including four playoff games) he scored 1 goal with 11 assists and was +9 with 14 penalty minutes. Aho had an even plus/minus with no points and 4 penalty minutes in five games for Sweden at the 2013 U18 World Junior Championship. He had 4 assists and 14 penalty minutes in six games as an assistant captain for Sweden at the 2013 U17 World Hockey Challenge. Sweden defeated Russia, 7-5, in the gold medal game.
2013-14: Aho played for Sweden's U18 team at the 2013 Ivan Hlinka Tournament in August before returning to Skelleftea. In his first 19 games with the club's mens team in the re-christened SHL he scored 1 goal with 3 assists and had an even plus/minus with 2 penalty minutes. Aho scored 4 goals with 8 assists and was +8 with 6 penalty minutes in his first 13 games with the Skelleftea U20 team. He was +1 with no points nor penalties in two games at the Ivan Hlinka Tournament; missing the final two games and the beginning of the season with a finger injury. Aho was ranked ninth amongst International skaters in Central Scouting's mid-term rankings prior to the 2014 NHL Draft.
Aho, not to be confused with the Finnish forward with the same name (no relation), is a puckmover with good vision and the ability to find teammates over the stretch of several zones. Very crafty with his stick and exudes confidence. Also likes to go on the rush with the puck and enter the opposition zone. Aho has spent this past winter becoming a more well-rounded power play point man and even found his way into 21 SHL games, where he played with a maturity few do at his age for the league’s best team. Isn’t afraid to get involved and apply his body in the process. Has shown a tendency to block shots and will apply the weight he has to play defensively. Aho generally seems solid in all facets of his game and can be the type of defenseman you either don’t notice or notice due to a strong individual action.
Aho is very small and is a spit in the bucket weight-wise. It is questionable whether he’ll have NHL potential over the long run. All assets of the game still require the proper nurturing and improvement.
Aho's high talent level makes him an intriguing prospect despite his small stature. While he will be challenged by the bigger and faster players at the NHL level his skill set suggests he could be an effective puck moving defenseman and power play quarterback in the future.