He played junior hockey for the Winkler Flyers before going to the University of North Dakota where he helped the school win the NCAA championship in the 1986–87 season.

The following year, Belfour signed as a free agent with the Chicago Blackhawks (after not being picked in the draft) alternating time between them and the Saginaw Hawks of the International Hockey League.

Belfour played for three seasons in the Manitoba Junior Hockey League with the Winkler Flyers, helping the team to a first-place finish in 1986.

As the starting goalie for the top team, Belfour finally received some notoriety and he joined the North Dakota Fighting Sioux for the 1986–87 season.

It was the last time a goalie led the league in Wins, Save%, and GAA until Carey Price achieved the feat in the 2014–2015 season.

Belfour helped lead the Blackhawks to the 1992 Stanley Cup Finals in the 1991–92 season, where they met the defending champion Pittsburgh Penguins.

Jaromír Jágr managed to score the tying goal with five minutes remaining, before a late one-man advantage for the Penguins proved key with Mario Lemieux putting a shot rebound past Belfour to give Pittsburgh the go-ahead lead with thirteen seconds left.

By January 1997, reports had surfaced that the two had an incident near a locker room that saw Belfour call Hackett "nothing more than a backup", although the two (along with their coach) asserted that they were more competitive with each other rather than having friction.

[6] A free agent after the season, Belfour was traded to the San Jose Sharks on January 25 for three players (right wing Ulf Dahlén, defenseman Michal Sýkora, goalie Chris Terreri) and a conditional second-round draft pick in the 1998 NHL Entry Draft after turning down an extension offer ($3.3 million) that would've raised his current rate ($2.75-million).

During the season, Belfour played 61 games and had a 1.88 GAA as his team won the Presidents' Trophy and made it to the Western Conference Finals only to lose to the Detroit Red Wings.

In the playoffs, Belfour won duels against past Vezina- and Stanley Cup-winning goaltenders Grant Fuhr and Patrick Roy, respectively.

The Stars won the Stanley Cup, beating the Buffalo Sabres in six games, capped by an incredible goalie duel against former backup Dominik Hašek that ended in a 2–1 win in the third overtime.

During the 2001–02 season, the Stars began to play poorly and there was a falling out between then-Stars coach Ken Hitchcock and GM Bob Gainey.

[10] Belfour rebounded after a dismal season with the Stars, winning a franchise-record 37 games and helping his new team finish second in the Northeast Division.

On April 3 in the final game of the season, Belfour posted a 6–0 shutout over the Senators to secure home ice advantage in the opening round of the playoffs.

However, in the second round, former teammate Jeremy Roenick eliminated the Leafs by putting a game 6 overtime goal past Belfour.

Belfour did not play during the NHL lockout in 2004–05, instead taking a minority stake in the projected Dallas Americans team in the proposed revival of the World Hockey Association while recovering and rehabilitating himself from primarily back-related injuries.

On July 1, 2006, Maple Leafs General Manager John Ferguson, Jr. released Belfour to free agency after posting a 22-22-4 record and a 3.29 GAA.

[16] On February 13, 2007, Belfour tied Hall of Famer Tony Esposito for eighth place on the career shutout list with his 76th in the Panthers' 1-0 blanking of the Montreal Canadiens.

Belfour's eagle has changed dramatically, from a rough Native looking style in Chicago, to a fierce competitive image in Dallas, while the background always features his current team's colours.

On the chin, there is an image of the logo for the Make-a-Wish Foundation, a charity very close to his heart, and the back plate highlights his passion for speed and restored cars.

Although he didn't play in any of the Olympic Games in Salt Lake City, he did add depth in goal to the strong Canadian team backing up Curtis Joseph and Martin Brodeur.

[20] Late in the 2006–07 season, Belfour, along with Panthers teammate Ville Peltonen, was arrested on April 9 outside of a South Florida nightclub and was charged with disorderly intoxication and resisting an officer without violence.