Hamilton scored 58 points (12 goals, 46 assists) in 67 games for his hometown Niagara IceDogs in the Ontario Hockey League during the 2010-11 season and was selected by the Boston Bruins with the No. 9 pick of the 2011 NHL Draft.

After helping Canada finish third at the 2013 IIHF World Junior Championship, Hamilton joined the Bruins and made his NHL debut on Jan. 19, 2013.

Hamilton played three seasons in Boston and scored 83 points (22 goals, 61 assists) in 178 games. He was traded to the Calgary Flames on June 26, 2015 for a first-round pick (forward Zach Senyshyn) and two second-round picks (forward Jakob Forsbacka Karlsson and defenseman Jeremy Lauzon) at the 2015 NHL Draft.

The Flames signed Hamilton to a six-year contract on June 30, 2015. He played three seasons with Calgary and scored an NHL career high 50 points (13 goals, 37 assists) in 2016-17.

Hamilton was traded again on June 23, 2018, to the Hurricanes, along with forward Micheal Ferland and defenseman Adam Fox, for defenseman Noah Hanifin and forward Elias Lindholm.

In his first season with the Hurricanes, Hamilton scored 39 points (18 goals, 21 assists) and helped them reach the 2019 Eastern Conference Final.

NOTES & TRANSACTIONS

• OHL Second All-Star Team (2011)
• Canadian Major Junior Scholastic Player of the Year (2011)
• OHL First All-Star Team (2012)
• Canadian Major Junior Defenseman of the Year (2012)
• Traded to Calgary by Boston for Calgary's 1st (Zachary Senyshyn) and 2nd (Jakob Forsbacks-Karlsson) round picks in 2015 NHL Draft and Washington's 2nd round pick (previously acquired, Boston selected Jeremy Lauzon) in 2015 NHL Draft, June 26, 2015.
• Traded to Carolina by Calgary with Micheal Ferland and Adam Fox for Noah Hanifin and Elias Lindholm, June 23, 2018.