His greatest single year with the Lightning came in 2003-04 when he helped lead the franchise to its only Stanley Cup championship. St. Louis won several individual honors that season, including the Art Ross Trophy as the NHL's point leader. He also won Hart Memorial Trophy as the NHL's Most Valuable Player and the Lester B. Pearson Award as the National Hockey League Players Association's Most Outstanding Player. He was also named a first team NHL All-Star.
Additionally, St. Louis played in six (2003, '04, '07, '08, '09, '11) NHL All-Star games, was a four-time All-NHL second team selection (2006-07, '09-10, '10-11, '12-13) and he won the Art Ross Trophy for the second time in 2012-13, becoming, at age 37, the oldest player in league history to be its single season leading scorer. St. Louis also won the NHL's Lady Byng Memorial Trophy three-times (2009-10, '10-11, '12-13), given to the player for his sportsmanship and gentlemanly play combined with a high standard of playing ability. St. Louis twice led the NHL in assists - with 56 in 2003-04 and with 43 in 48 games played in 2012-13.
A native of Laval, Quebec, St. Louis played college hockey for the University of Vermont, leading the Catamounts to the NCAA Frozen Four in 1996 while earning All-America status in three of those years (1994-95 through 1996-97). Internationally, St. Louis was a two-time Olympian (2006, 2014), winning a gold medal with Team Canada in 2014. In addition to playing for the Lightning from 2000-01 through 2013-14, he played for the Calgary Flames (1998-99 through 1999-2000) and the New York Rangers (2013-14 through 2014-15).