Carl Oliver Hagelin (born 23 August 1988) is a Swedish former professional ice hockey player who played eleven seasons in the National Hockey League (NHL) for the New York Rangers, Anaheim Ducks, Pittsburgh Penguins, Los Angeles Kings, and Washington Capitals.

Prior to beginning his collegiate career, Hagelin played two seasons for Södertälje SK's team in the J20 SuperElit.

[3] As a junior in 2009–10, Hagelin helped Michigan win the CCHA championship and was named as an Academic All-Big Ten.

By his final season on the team, fans had taken to regularly displaying Swedish flags as an expression of their high regard for him.

[19] After Adam Henrique of the New Jersey Devils pulled out of the 2012 NHL All-Star Rookie Showcase due to injury, Hagelin took his spot and was slated to take part in the Fastest Skater challenge during the Skills Competition, ultimately winning the competition after beating Ottawa Senators rookie Colin Greening with the fastest final round time ever recorded, 13.218, later beaten by Jonathan Drouin in 2015.

[20] On 15 April 2012, Hagelin received a three-game suspension for elbowing Ottawa Senators captain Daniel Alfredsson in the head during New York's loss in Game 2 of the Eastern Conference Quarterfinals.

On 24 April 2015, Hagelin scored the series-clinching goal in overtime of Game 5 of the 2015 Eastern Conference Quarterfinals against the Pittsburgh Penguins.

With 12 points in 43 games, Hagelin was traded by the Ducks to the Pittsburgh Penguins in exchange for forward David Perron and defenseman Adam Clendening on 16 January 2016.

Although that season was marred by injury and low point production, Hagelin did score the final goal of the playoffs, an empty netter in game six, which sealed the 2–0 victory.

[34] Hagelin's older brother Bobbie is a former professional ice hockey player for Södertälje SK in the Swedish Elite League and for Rødovre Mighty Bulls in the Danish AL-Bank Ligaen.