[2] His father was involved in local ice hockey teams, while his mother played basketball and track and field.

[3] He began playing ice hockey at the age of nine, comparatively late by Canadian standards, and temporarily quit after only a year.

[11] Although the Colts' OHL postseason run came to an end with a loss to the North Bay Battalion in the second playoff round, Blackwood was praised by coaches for his performance during the season, and he was expected to remain Barrie's starting goaltender for the remainder of his junior hockey career.

[19] On December 27, Blackwood recorded his first NHL win, a 5–2 victory over the Boston Bruins, with another strong performance, making 40 saves on 42 shots.

[23] On January 3, 2019, Blackwood was named to the North Division roster for the 2019 American Hockey League All-Star Classic.

[27] As a pending restricted free agent with the Devils at the conclusion of his three-year contract, Blackwood was traded to the San Jose Sharks in exchange for a 2023 sixth-round pick on June 27, 2023.

[29] His debut for the Sharks came in the early stages of the 2023–24 season on October 14, in a 2–1 shootout loss to the Colorado Avalanche, in which he made 51 saves.

[36] On April 29, 2019, Blackwood was named as the third-choice goaltender to the senior Canadian roster for the 2019 IIHF World Championship held in Slovakia.

[37] He made his debut for Canada in a relief appearance, replacing Carter Hart for nine minutes in a 5–0 round robin victory over Denmark on May 20.