Spencer Gill was born in Riverview, New Brunswick, Canada.
Gill played amateur hockey for the Moncton Flyers in 2021-2022. He played between three leagues and he finished with seven goals and 32 assists in 40 games total. Gill was selected fifth overall by Rimouski in the 2022 QMJHL draft.
In his first season for the Oceanic, he played 41 games and had four assists. During the season, he also played for Team Canada White U17 and had two goals in six games.
THis past season, Gill broke out at Rimouski and played 65 games and scored 12 goals and 34 assists. He also was selected to play in the WJC-18 for Canada and had two assists in seven games.