[3] The cold temperatures in Stratford meant that McCann spent his childhood playing ice hockey outside on frozen ponds.

[6] In 64 games with his junior ice hockey team during the 2012–13 season, McCann scored 21 goals and recorded 23 assists.

[9] In Game 1 of that year's OHL playoffs, McCann was checked by Cameron Brace of the Owen Sound Attack.

[10] He was ultimately diagnosed with a concussion and severe case of whiplash, which kept him out of the lineup indefinitely, and Brace was given a five-game suspension for the play.

The following game, on October 10, he scored his first NHL goal against Jonas Hiller of the Calgary Flames in a 3–2 OT loss.

"[17][18] On November 1, 2015, the Canucks announced that McCann and fellow rookie Jake Virtanen would remain in the NHL beyond their nine-game tryout period.

[21] At the time of the transaction, Canucks general manager Jim Benning thought his team needed a physical defenceman, while the Panthers felt that McCann was a better fit for its possession-based style of hockey than Gudbranson.

[32] McCann was expected by both Pittsburgh and Toronto to be an expansion draft casualty to the arriving Seattle Kraken; the Penguins used him to re-acquire Hållander and allow another player to be selected from their roster,[33] while the Maple Leafs (who did not have enough space for a protection slot under expansion draft rules) acquired McCann for the purpose of enticing the Kraken to select him over forward Alexander Kerfoot and defenceman Justin Holl.

[36] During the preseason, McCann played on the Kraken's top line in the centre position between Jaden Schwartz and Jordan Eberle.

[50] McCann missed three games to recover before rejoining the Kraken lineup on March 5 and playing 16:21 minutes of ice time in a 5–2 loss to the Washington Capitals.

[52] Although the Kraken failed to qualify for the 2022 Stanley Cup playoffs,[53] McCann had a career-best season with 27 goals and 23 assists for 50 points.

[54] On April 29, 2019, McCann was named to his first Team Canada roster for the 2019 IIHF World Championship held in Slovakia.

[55] McCann helped Canada progress through to the playoff rounds before losing the final to Finland, finishing with the silver medal.