As a youth, DeKeyser played in the 2003 Quebec International Pee-Wee Hockey Tournament with the Detroit Little Caesarsminor ice hockey team. He later played midget hockey with the Compuware AAA program from 2006 to 2008, before signing with the Trail Smoke Eaters of the British Columbia Hockey League for the 2008–09 season, where he recorded eight goals and 17 assists in 58 games. For his efforts, he was named the Trail Smoke Eaters' Defenseman of the Year. During the 2009–10 season, DeKeyser played for the Sioux City Musketeers of the United States Hockey League, where he recorded one goal and ten assists in 41 games. Following the 2009–10 season, DeKeyser committed to play college ice hockey for the Western Michigan Broncos. During the 2010–11 season, DeKeyser appeared in 42 games, where he recorded five goals and 12 assists. He was named to the Central Collegiate Hockey Association All-Rookie team, and named to the CCHA All-Tournament Team for tallying two assists and helping shut down the University of Michigan’s high-powered offense during the CCHA Semifinals and Finals. DeKeyser ranked second on the team in plus-minus with a +12 rating, and led the team in blocked shots with 54. DeKeyser recorded his first collegiate goal on October 8, 2010, in a game against Canisius College. During the 2011–12 season, DeKeyser appeared in 41 games, where he recorded five goals and 12 assists. He was named to the Second Team All-American, Second Team All-CCHA, CCHA Best Defensive Defenseman, and CCHA All-Tournament Team. He became just the second Bronco player in program history to be named CCHA Best Defensive Defenseman. During the 2012–13 season, DeKeyser appeared in 35 games, where he recorded two goals and 13 assists. He was named to the First Team All-CCHA, and became the first Bronco to be named CCHA Best Defensive Defenseman twice after winning it in consecutive seasons. In three seasons with the Broncos, DeKeyser racked up 12 goals and 37 assists in 118 games.
Professional
After three years with Western Michigan, DeKeyser was being pursued by multiple teams around the NHL. Eventually, he decided to play for his hometown team and signed a two-year contract with the Detroit Red Wings on March 29, 2013. He began playing for Detroit one week later and recorded his first NHL point against the Nashville Predators on April 14, 2013, assisting on a Henrik Zetterberg goal. DeKeyser appeared in 11 regular season and two post-season games for the Red Wings during the 2012–13 season. Following the conclusion of Detroit's Stanley Cup playoff run in 2013, he joined the Grand Rapids Griffins of the American Hockey League during the 2013 Calder Cup playoffs, where he recorded one assist in six games and helped the team capture their first-ever Calder Cup championship. On November 4, 2013, DeKeyser scored his first career NHL goal in a game against the Winnipeg Jets. During the 2013–14 season, DeKeyser recorded four goals and 19 assists, as well as a +10 rating, in 65 games. He ranked among the NHL's top rookie blueliners in points, plus-minus and ice time. He also placed third among all rookies, and second on Detroit overall, with 116 blocked shots. On September 16, 2014, the Red Wings signed DeKeyser to a two-year, $4.375 million contract extension. DeKeyser was named the 2014 Detroit Red Wings–Detroit Sports Broadcasters Association Rookie of the Year, receiving the award in a pre-game ceremony on November 9, 2014, at Joe Louis Arena. On July 26, 2016, the Red Wings signed DeKeyser to a six-year, $30 million contract.
