[3] Prior to the 2009–10 WHL season Hamonic was named the co-captain of the Warriors alongside Jason Bast.

[6] The Wheat Kings earned a spot in the 2010 Memorial Cup as hosts of the round-robin tournament which included the champions of the three Canadian major junior hockey leagues.

Brandon advanced to the Memorial Cup final after upsetting the WHL champion Calgary Hitmen in the semifinal.

[6] On November 24, 2010, after spending 19 games in the American Hockey League (AHL) with the Islanders' top minor league affiliate, the Bridgeport Sound Tigers, Hamonic made his NHL debut, putting in a strong performance for New York, who ultimately lost in overtime against the Columbus Blue Jackets.

[9] Hamonic finished his rookie season with a total of five goals and 26 points in 62 games in a top-four role with the Islanders.

In the midst of the 2012–13 NHL lockout, Hamonic returned to the Islanders' affiliate in Bridgeport and posted ten points in 21 games.

[11] Early in the 2015–16 NHL season, it was revealed that Hamonic had requested a trade specifically to Western Canada due to family reasons.

[14] On April 23, 2018, Hamonic was nominated for the King Clancy Memorial Trophy as a player who best exemplifies leadership qualities on and off the ice and gives back to his community.

[18] Following the Flames 2018–19 season opener loss to the Vancouver Canucks on October 3, 2018, Hamonic was placed on injured reserve to recover from a facial fracture following a fight with Erik Gudbranson.

[22] On July 10, 2020, Hamonic announced he opted-out of the 2020 Stanley Cup playoffs due to concerns surrounding the COVID-19 pandemic after the NHL made plans to finish the season.

[24] As an unrestricted free agent from the Flames, Hamonic remained un-signed entering training camp for the delayed 2020–21 season.

On January 4, 2021, he agreed to an invitation to attend the Vancouver Canucks training camp on a professional tryout basis.

[25] Nearing the conclusion of camp, Hamonic agreed to a one-year, $1.25 million contract with the Canucks on January 12, 2021.

Canada advanced to the semifinals and in their game versus Switzerland, he was checked from behind by Jeffrey Fuglister in the final minute of play.

However, Hamonic suffered a separated shoulder on the play and missed the game,[36] which Canada lost, earning the team a silver medal.

[40] Hamonic and his wife also take part in The Northern Project initiative which provides Indigenous children from the Northwest Territories, Nunavut and Yukon the opportunity to visit Calgary.