Dawes played junior ice hockey for the Kootenay Ice in the Western Hockey League. In his first year, the Ice won the Memorial Cup after winning the President's Cup as champions of the WHL. Dawes improved his play in his next two seasons in the WHL, and, for the 2003–04 season, he was named a first team All-Star in the Western Conference, the winner of the Brad Hornung Trophy, and the Ice's most valuable player. Dawes was drafted in the fifth round, 149th overall, in the 2003 NHL Entry Draft by the New York Rangers, after two seasons in the WHL. After three seasons of junior hockey and four games in the American Hockey League for the Hartford Wolf Pack at the end of the 2003–04 season, the Rangers signed Dawes to his first professional contract on September 1, 2004, when he was 19 years old. Dawes went on to play another season with the Ice, recognized for his talent as a finalist for the Four Broncos Memorial Trophy, before breaking into the professional game in the AHL. Dawes finished his Kootenay Ice career as the franchise leader in goals, with 159 scored in 245 games. Dawes scored his first NHL goal against Andrew Raycroft on October 21, 2006, in the Rangers 5–4 win over the Toronto Maple Leafs. After playing in seven games then being a healthy scratch for seven of the next eight, Dawes was sent down to play with the Wolf Pack for the rest of the 2006–07 season. He returned to play in the Rangers' final game of the playoffs on May 6, 2007. Game six against the Buffalo Sabres in the Eastern Conference Semifinals was Dawes's first NHL playoff game. While Dawes was trying to block a shot, the first Sabres goal deflected off of his body to go into the net past goalie Henrik Lundqvist. The Rangers lost the game 5–4 to lose the series 4–2. Dawes recorded his first NHL assist in the 2007–08 season. Dawes had become a good shootout option for the Rangers, scoring four times on seven attempts at that point. During regular play, played as high as the second line at points during the 2007–08 season. On July 16, 2008, Dawes re-signed with the Rangers to a one-year, $587,500 contract. On March 4, 2009, Dawes was traded to the Phoenix Coyotes along with Dmitri Kalinin and Petr Průcha for Derek Morris. On July 16, 2009, Dawes was claimed off waivers by the Calgary Flames. On September 8, 2010, Dawes signed a one-year, two-way contract with the Atlanta Thrashers worth $600,000 in the NHL and $105,000 in the AHL. He was traded on February 24, 2011, to the Montreal Canadiens, along with Brent Sopel for Ben Maxwell and a 4th-round pick in the 2011 NHL Entry Draft. On May 31, 2011, Dawes left the NHL and signed a one-year contract with Kazakh based KHL team, Barys Astana. He continued the relationship through the 2017-18 season. On July 14, 2020, Dawes as a free agent and the fifth leading scorer in KHL history extended his tenure in Russia, signing a one-year contract with Ak Bars Kazan.
