Lucas Gaudreault played junior hockey for HC La Chaux-de-Fonds and HC Fribourg-Gottéron. After three seasons with the Dragons, he signed with the HC Düdingen Bulls.
In the 2019-20 season, he appeared in 16 games for them, posting a 3.84 goals-against average. As the 2020-21 season was canceled, Gaudreault did not play this season. He served, however, as Genève-Servette HC's third goalie during the playoffs.