McMillan is most notable for winning the 2017 Tour Challenge Tier 2 Grand Slam of Curling event playing second for Jason Gunnlaugson.

[5] They also won The Sunova Spiel at East St. Paul and the Thistle Integrity Stakes the following two months and had semifinal appearances at both the DeKalb Superspiel and the KKP Classic.

[7] The following season, the team would only win one tour event, the Atkins Curling Supplies Classic, where they went undefeated to claim the title.

As the reigning provincials champions, Team Jason Gunnlaugson was chosen to represent Manitoba at the 2021 Tim Hortons Brier.

[17] Due to their early success, Team Calvert qualified for the 2021 National Grand Slam event, where they finished with a 1–3 record.