Garth Snow was drafted 114th overall in the 1987 Entry Draft by the Québec Nordiques. On December 3, 1993, Garth made his NHL debut with a win against the Islanders. He played five games that season and recorded a 3-2 record. After playing two NHL games in the shortened 1994-95 season, Garth was traded from the Colorado Avalanche (née Québec) to the Philadelphia Flyers on July 12, 1995 for a pair of draft picks. In his first season with his new team, Garth shared goaltending duties with Ron Hextall and posted a 12-8-4 record in his 26 games. More importantly, he helped the Flyers win the Atlantic Division title. In 1996-97, Garth played 35 games and went 14-8-8 with a 2.52 goals-against average. In the playoffs, Garth helped the Flyers win the Prince of Wales Trophy in the Eastern Conference finals before losing to the Red Wings in the Stanley Cup finals.
In 1997-98, Garth was traded on March 4 to the Vancouver Canucks for Sean Burke. In 41 games split between the two teams, Garth posted a 17-15-4 record. In 1998-99, Garth took on the Canucks' number one goaltending duties and posted a 20-31-8 record with six shutouts and a 2.93 GAA. In 1999-2000, he shared goaltending duties first with Kevin Weekes and then with Félix Potvin and posted a 10-15-3 record.
In 2000-01, Garth signed with the Penguins in October 2000. On December 27, Garth recorded a 5-0 shutout victory against the Maple Leafs in Mario Lemieux's comeback. In 35 games that year, he went 14-15-4 with a 2.98 GAA. In the playoffs, as Johan Hedberg's goaltending partner, Garth helped the Penguins reach the Eastern Conference finals.
On July 1, 2001, Garth signed as a free agent with the New York Islanders.