[3] St. Croix made his NHL debut for the Flyers during the 1977–78 season on February 16, 1978 at the Spectrum against the Minnesota North Stars.

[3][5] 1980-81 was St. Croix's first full season in the NHL, in which he split time as the Flyers' goaltender with Pete Peeters and Phil Myre.

[2][4][9] St. Croix's final season in the NHL was 1984–85, which he split between the Maple Leafs and the St. Catharines Saints in the AHL.

Prior to the 2011–12 season, the team was relocated to Newfoundland and renamed the St. John's IceCaps where St. Croix continued to serve as an assistant coach/goaltending coach.

[2] In September 2012, with the resignation of Francois Allaire, St. Croix was hired as the Toronto Maple Leafs goaltending coach.

[13] When the IceCaps returned as the Manitoba Moose in 2015, St. Croix rejoined the organization as developmental goaltending coach and scout until he retired in 2021.