Junior and minor leagues

Dafoe has played for WHL sides Portland Winter Hawks (1986–1990) and Prince Albert Raiders (1990–1991), ECHL side Hampton Roads Admirals, AHL sides Baltimore Skipjacks (1991–1992 and 1992–1993), New Haven Nighthawks (1992) and Portland Pirates (1993–1994 and 1994–1995), and IHL side Phoenix Roadrunners. He was voted a First Team AHL All-Star in 1993-94 and won a Calder Cup championship that season with the Portland Pirates.

During Dafoe's time with the Winter Hawks, he had an on-ice fistfight with Tri-City Americans goaltender Olaf Kölzig, someone with whom he would go on to have a friendly rivalry in the NHL—so friendly that they served as each other's best man when they got married. He and Kolzig also had a "friendly" fight later in their NHL careers on November 21, 1998, when the Boston Bruins took on the Washington Capitals. During the game, a fight broke out that was so violent and all encompassing, the goalies (Dafoe and Kolzig) also got caught up in it. The fight between the goalies was primarily comedic, with both Dafoe and Kolzig laughing as they landed punches.

Washington Capitals

Dafoe was drafted 35th overall in the second round of the 1989 NHL Entry Draft by the Washington Capitals, and made his NHL debut in the 1992–93 NHL season. Dafoe was one of two goalies taken by Washington in that draft, as they used their first round pick to select Olaf Kölzig. After appearing in just one game in 1992–93, Dafoe got into five the next season while veterans Don Beaupre and Rick Tabaracci handled the bulk of the work. In the 1994–95 NHL season Dafoe suited up for four games, in part due to the emergence of another second round pick, 1992 selection Jim Carey, who took the NHL by storm as a rookie. The Capitals had an abundance of riches in goal and packaged Dafoe with winger Dmitri Khristich and traded them to the Los Angeles Kings for a first and fourth round draft pick.

Los Angeles Kings

With the Kings, Dafoe not only became an NHL regular but stepped into the starter's role while the previous incumbent, Kelly Hrudey, became his backup. Dafoe played 47 games but won just 14 with a struggling Kings club and posted the worst goals against and save percentage numbers on the team. The following year, Hrudey was with the San Jose Sharks, and Dafoe shared the crease with Stephane Fiset. The duo posted very similar numbers for the club, but in the offseason, the Kings made Fiset their goaltender going forward and Dafoe was again packaged with Dmitri Khristich, and dealt to the Boston Bruins.

Boston Bruins

With the Bruins, he stepped into the starter's role, pushing aside Jim Carey, who had replaced him back in Washington. Dafoe excelled in Boston, playing 65 games and posting 30 wins with 6 shutouts. The following season, Dafoe helped the Bruins return to the playoffs and win a postseason series. He posted career-best numbers in 1998-99 with a 1.99 goals against average and a .926 save percentage. He finished third in voting for the Vezina Trophy, and was named to the NHL Second All-Star Team, edging out Curtis Joseph in the voting.

Dafoe held out for part of the 1999–2000 season during a contract dispute with Bruins general manager Harry Sinden, and in his return suffered injuries, resulting in a regression from his previous year. He spent three more seasons in Boston, and after playing 41 and 45 games the previous two seasons, in 2002 he played 64 games and won a career-best 35 of them, setting himself up nicely for a new contract. However, when Boston was upset by the Montreal Canadiens in the 2002 post season the Bruins let Dafoe become a free agent.

That summer, the free agent pool included a lot of top netminders including Mike Richter, Ed Belfour and Curtis Joseph, and while the aforementioned earned new contracts, Dafoe remained a free agent as the 2002-03 season began. Nearly two months into the season, Dafoe agreed to a one-year deal with a player's option for a second to join the Atlanta Thrashers.

Atlanta Thrashers

Thrashers general manager Don Waddell was thrilled to add Dafoe to his club, saying "He's a proven goaltender. His stats prove he's not only a No. 1 goaltender, but one of the top goaltenders in this elite league of the NHL."^[1] That optimism proved to be misplaced as Dafoe struggled mightily in Atlanta, posting just five wins in 17 games, and a bloated 4.36 goals against average. He exercised his player option and returned for the 2003-04 season and while his play improved with the goals against cut down dramatically to 3.14, he was an afterthought for the club playing just 18 games and winning only four.

Dafoe retired from professional hockey following the 2004–05 NHL lockout.