Carlson made his professional debut for the Capitals' American Hockey League affiliate, the Hershey Bears, on May 2, 2009, in a Calder Cup playoff game against the Wilkes-Barre/Scranton Penguins. The following night, he scored his first professional goal in Game 2 of the series. Carlson made his NHL debut for the Capitals on November 21, 2009, against the Toronto Maple Leafs. On January 21, 2010, Carlson was recalled by the Capitals. On March 25, 2010, Carlson scored his first NHL goal, against Cam Ward of the Carolina Hurricanes. In Game 2 of the Capitals' 2010 Stanley Cup playoff first-round series against the Montreal Canadiens, Carlson scored his first NHL playoff goal, tying the game with just over one minute to play in regulation. After the Capitals' elimination in the playoffs, Carlson rejoined the Hershey Bears in their playoff campaign and scored the game- and Calder Cup-winning goal in Game 6 of the Calder Cup Final against the Texas Stars. On September 14, 2012, Carlson signed a six-year, $23.8 million contract extension with the Capitals. in 2016 Carlson's 2015–16 season was interrupted by an injury that limited to him playing just 56 regular season games. Carlson was injured in late December 2015, and his injury emerged again throughout the second half of the 2015–16 season. Despite the injury, Carlson scored 39 points by the end of the regular season. During the 2017–18 season, the last year of his contract, Carlson had a career year, putting up career numbers in goals and assists. He played in all 82 games during regular season, and his success helped push the Capitals to the 2018 playoffs. At the conclusion of the regular season, Carlson led NHL defensemen in points and became the first Capitals defenseman since Mike Green in the 2009–10 season to score 60 points in a season. On June 24, 2018, having just won the Stanley Cup with Washington, Carlson signed an eight-year, $64 million contract extension with the Capitals. Returning to the Washington lineup after an injury for a November 11, 2018, for a game against the Arizona Coyotes, Carlson skated in his 623rd career game as a defenseman, passing Sylvain Côté for sixth place in games played for the Capitals. He had missed one game with a lower-body injury announced on November 9, 2018.
International play
Carlson was an alternate captain for the United States in the 2010 World Junior Ice Hockey Championships. On January 5, 2010, he scored the game-winning goal in overtime of the gold medal game as part of a two-goal effort to defeat Canada 6–5. Additionally, he was named to the tournament's all-star team. In December 2010, Carlson was named to NHL.com's All-Time World Junior Championship team. On January 1, 2014, Carlson was named to the U.S. roster for the 2014 Winter Olympics in Sochi. On February 13, 2014, he scored the Americans' first goal of the tournament, at 15:27 of the first period of the nation's opening match against Slovakia. His goal was scored on his first shot in the tournament, giving him consecutive goals on shots in international play for the U.S.
Personal life
Carlson was born in Natick, Massachusetts, but grew up in the Colonia section of Woodbridge Township, New Jersey, after moving as a five-year-old. Carlson is of Swedish descent. On September 6, 2014, Carlson married his long-time girlfriend Gina Nucci, and in June 2015, they had their firstborn child, a son. They had their second child in May 2018.
