Edmundson has also previously played for the Carolina Hurricanes, Montreal Canadiens, Washington Capitals, and Toronto Maple Leafs.

[2] Growing up in Manitoba, Edmundson and his brother played junior ice hockey with their hometown midget AAA team, the Brandon Wheat Kings.

[7] In his WHL rookie season, Edmundson played in 71 games for the Warriors and scored 20 points while adding on 95 penalty minutes.

[1] Due to the 2012–13 NHL lockout, Edmundson was unable to attend the Blues' 2012 Training Camp prior to the start of the season.

[16] He returned to the WHL for his final season of major junior hockey, and was named an alternate captain alongside Morgan Rielly and Jordan Wyton.

[18] While playing with the Blazers, Edmundson signed a three-year entry-level contract with the Blues to conclude his junior career after the season finished.

[19] After the regular season concluded, Edmundson received the team's Most Dedicated award[20] as the Blazers qualified for the 2013 WHL Playoffs.

[22] Edmundson began his professional career with the Blues' American Hockey League (AHL) affiliate, the Chicago Wolves, after being cut from training camp.

[35] Entering the second year of his newest contract, Edmundson again made the Blues opening night roster prior to the 2017–18 season.

[38] Playing primarily with either Alex Pietrangelo or Colton Parayko, Edmundson finished the season with a career high 17 points in 69 games.

[39] During the 2018 off-season, Edmundson volunteered as a guest instructor at Micheal Ferland's Hockey School in Brandon, Manitoba, alongside Brigette Lacquette, Harley Garrioch, Jens Meilleur, Ryan Pulock, Tyler Plante, Shaq Merasty, Josh Elmes, and Zach Whitecloud.

[45] As a restricted free agent in the off-season, Edmundson filed for salary arbitration and was awarded a one-year, $3.1 million contract to remain with the Blues.

[citation needed] On September 12, 2020, Edmundson (a pending unrestricted free agent) was traded to the Montreal Canadiens in exchange for a 2020 fifth-round pick.

[63] On July 1, 2024, having left the Maple Leafs as a free agent, Edmundson signed a four-year, $15.4 million contract with the Los Angeles Kings.

[65] After missing the first game of the tournament due to a groin injury, Edmundson scored three points in Canada's 10–0 win over South Korea on May 6, 2018.