Born in Laval, Quebec, Martin St. Louis was a top offensive performer for four years at the University of Vermont following his season with the Hawkesbury Hawks in 1992-1993. During his senior year in 1996-97 he led the ECAC with 36 assists in as many games. St. Louis was placed on the Conference First All-Star team and named an NCAA East First Team All-American three times and was voted on to the NCAA Championship Tournament All-Star team in 1996. After graduating the three-time Hobey Baker finalist was undrafted and unsigned and opted to join the Cleveland Lumberjacks of the IHL.

St. Louis enjoyed a fine rookie pro season which was capped by signing a contract with the Calgary Flames midway through the schedule. Over the next two years he apprenticed with the AHL's Saint John Flames and saw action as a role player in Calgary. In July 2000 St. Louis signed with Tampa Bay and enjoyed a solid 18-goal season in his first year with the club. The Laval native was on his way to a career year offensively in 2001-02 before suffering a broken leg that ended his season.

A highly skilled and energetic player St. Louis returned in 2002-03, quickly establishing himself as one of the biggest surprises of the NHL season scoring a career high 33 goals and 70 points while making his All-Star Game debut and leading the Lightning to the second round of the Stanley Cup playoffs for the first time in team history.

Coming off a career year in 2002-03, St. Louis continued his strong play in 2003-04. The former UVM Catamount bettered his previous year totals, leading not only his team but the NHL in scoring with 94 points and by doing so captured his first Art Ross and becoming the first collegiate player to lead the league in scoring. St. Louis finished tied for second in the Maurice Richard goal scoring race with 38 goals and finished tied for first in assists with 56 while leading the Lightning to first place in the South East Division.

St. Louis continued his strong play in the post season, finishing second in playoff scoring with 24 points (9-15-24) while helping the Tampa Bay Lightning capture their first Stanley Cup title, with a hard fought seven game series win over the Calgary Flames. Coming off a Stanley Cup win, St. Louis ended his NHL season by winning the Lester B. Pearson award, as the league's top player, as voted by his peers, as well as the Hart Trophy as the league's Most Valuable Player.

Following his unforgettable season with the Lightning, St. Louis helped Team Canada capture the World Cup of Hockey in the summer of 2004. In 2005-06, following St. Louis' career year with the Lightning the crafty forward was selected to compete for Team Canada in the 2006 Winter Olympics where, despite his best efforts, he would return to Tampa Bay without a medal. Two years later, St. Louis would represent his homeland once again, this time at the World Championships. Despite his best efforts however, St. Louis and Team Canada would earn only a silver medal.

Prior to his appearance in the World Championships, St. Louis was the only Lightning player to appear in all 82 games and the former league MVP averaged 24:17 in ice time per game, leading all NHL forwards.