[2] Both of his parents participated in the 1984 Olympic Games in Los Angeles: his father Doug was a rower in the men's quadruple sculls, while his mother Lynn was a point guard for the Canadian women's basketball team.

[10] Hamilton made his Stanley Cup playoff debut on May 3, replacing defenceman Andrew Ference, who was serving a one-game suspension for his illegal hit on Toronto Maple Leafs forward Mikhail Grabovski.

On April 25, Hamilton was named the 44th Annual NESN 7th Player recipient, an award given to the Bruin who most exceeded all expectations that season, as voted by the team's fans.

[17] On June 23, 2018, Hamilton was traded to the Carolina Hurricanes (along with teammate Micheal Ferland and prospect Adam Fox) in exchange for Elias Lindholm and Noah Hanifin.

[20] As a result of the COVID-19 pandemic, the NHL season was paused, and delayed for several months allowing Hamilton to return for Carolina's final five games of the 2020 Stanley Cup playoffs.

[22] Coming back from injury while playing on an expiring contract, Hamilton had another stellar year, finishing the 2020–21 season fourth in Norris Trophy voting.

[23] After three productive seasons with the Hurricanes, Hamilton left the club as a free agent and on July 28, 2021, he signed a seven-year, $63 million contract with the New Jersey Devils.

[26] His older brother Freddie was drafted by the San Jose Sharks in 2010 and played for the Colorado Avalanche, Calgary Flames, and Arizona Coyotes.