2008-09: Gregory Hofmann split the season between Ambri-Piotta's U-17 and U-20 squads. In 20 games for the U-17 squad, Hofmann scored 9 goals and added 16 assists for 25 points. In 22 games for the U-20 team, Hofmann scored 10 goals and added 7 assists for 17 points. Hofmann registered no points in 2 playoff games for the U-20 team.
2009-10: Hofmann spent most of the season with Ambri-Piotta's U-20 squad. In 34 games, he scored 25 goals and added 30 assists for 55 points. In 3 playoff games for that team, Hofmann scored 1 goal and added 2 assists for 3 points. Hofmann played for Switzerland at the 2010 U-18 World Junior Championship, scoring 5 goals in 6 games. He was named a Top 3 player for the Swiss squad.
2010-11: Hofmann played for HC Ambri-Piotta in Switzerland's top league. In 41 games, Hofmann scored 3 goals and added 9 assists for 12 points to go along with 42 penalty minutes. He was named the Best Rookie in the NLA. In 17 games in the relegation round, Hofmann scored 1 goal and added 4 assists for 5 points. Hofmann played for Switzerland at the 2011 U-20 World Junior Championship, scoring 1 goal and adding 3 assists for 4 points in 6 games.
2011-12: Hofmann played in Switzerland's Elite League with Ambri-Piotta and played for the Swiss national team in the 2012 U20 World Junior Championship. In a limited role he scored 5 goals with 1 assist in 34 games and had 6 penalty minutes. Ambri-Piotta was forced to avoid delegation to the B division after finishing 11th out of 12 teams. Hofmann scored 1 goal with 1 assist in four qualifying games. In six games for eighth-place Switzerland at the WJC he scored 1 goal with 1 assist and was minus-two.
Hofmann is playing for Davos in the Swiss A League for the 2012-13 season.