Whitney started his professional career in the 1991-92 season, playing with teams in the German Deutsche Eishockey Liga and the International Hockey League, as well as two games with the San Jose Sharks.

Whitney has played for several different NHL teams during his 24-year career, including the San Jose Sharks (1991–92 to 1996–97), Edmonton Oilers (1997–98), Florida Panthers (1997–98 to 2000–01), Columbus Blue Jackets (2000–01 to 2002–03), Detroit Red Wings (2003–04), Carolina Hurricanes, Phoenix Coyotes, and Dallas Stars (details below).

In his first season with the Hurricanes in 2005–06, Whitney helped Carolina win their first Stanley Cup with fellow Fort Saskatchewan native Mike Commodore.

Whitney was the last remaining member of the San Jose Sharks inaugural team (1991–92) active in the NHL until his retirement on January 21, 2015.

On March 31, 2012, Whitney became only the 79th player in the history of the NHL to score 1,000 regular-season points, when he registered an assist in a game against the Anaheim Ducks.

On January 21, 2015, he announced his retirement as an NHL player, ending a career after producing 1,064 points (385-679) in 1,330 regular-season games.

Whitney notched seven points in 10 games at the 1999 World Championship, again missing a medal when Canada lost in the semifinals to the Czech Republic.