In the summer of 1999, during a camp held by Ron Fournier, he told Réseau des Sports that his goal was to make it to the NHL.

[2] Said to have "an exceptional talent",[3] he became a Level VI referee in the Hockey Canada Officiating Program during a seminar in November 2001, held in Halifax, Nova Scotia.

[14] He worked the 2002 Memorial Cup,[15] including the final game between the Victoriaville Tigres of the QMJHL and the Kootenay Ice of the Western Hockey League.

[17][c] As he began to work games in the QMJHL, St-Laurent was hired by the American Hockey League as a linesman for the 1999–00 AHL season.

[27] During the 2015–16 AHL season, St-Laurent worked two games as part of a rehabilitation assignment, marking his first appearance in the league since the summer of 2009.

[60][j] St-Laurent worked the 2020 NHL All-Star Game, held at Enterprise Center in St. Louis, Missouri on 25 January.

He also helped work the Skills competition the night before, along with referee Justin St. Pierre and linesmen Michel Cormier and Bryan Pancich.

[63] St-Laurent has also worked the 2018 NHL Global Series,[64] including an exhibition game between Kölner Haie and the Edmonton Oilers.

[65] During the 2006–07 season, St-Laurent tore a ligament in his knee, which forced him to sit out a month's worth of AHL and NHL games.

[76] On 22 April 2014, St-Laurent worked Game Four of the Eastern Conference Quarterfinal series between the Montreal Canadiens and the Tampa Bay Lightning.

[77] During the second intermission, CBC's Ron MacLean spoke up about St-Laurent's participation in the game, saying that he "would not have been a popular choice for the Tampa Bay Lightning".

[79] Late in the second period of a game between the Winnipeg Jets and Tampa Bay Lightning, played on 18 February 2016, Anton Stralman delivered a questionable hit to Bryan Little.

Another shot showed what appeared to be him laughing about something; this gave the commentators the impression that the laughter stemmed from him ejecting Maurice.

[85] In September 2016, St-Laurent said that his laughter was unrelated to Maurice; Winnipeg's Dustin Byfuglien cracked a joke shortly after the ejection.

[90] During the 2002–03 ice hockey season, St-Laurent was assigned to work the 2003 IIHF World Championship Division 1A tournament, held in Budapest, Hungary.

[92][l] In a 2010 episode of HBO's 24/7 series involving the Pittsburgh Penguins and Washington Capitals, St-Laurent was seen talking to Bruce Boudreau about penalties that were issued early in the first period of a preview of the teams' Winter Classic.

[93][citation needed] The next year, during the 24/7 series involving the New York Rangers and Philadelphia Flyers, a quick camera shot showed him giving Ryan Callahan a cross-checking penalty.

[94] A segment during an October 2015 episode of NESN's Behind the B followed St-Laurent through the course of the Boston Bruins' home opener against the Winnipeg Jets.

[95] In the winter of 2007, St-Laurent took part in the first "Zebras Care" program that the National Hockey League Officials Association put together.