As a child actor, Reid provided the voice of the title character in Franklin, Tommy Settegren in 1997's Pippi Longstocking, and has since co-starred in Strange Days at Blake Holsey High, among other shows. Reid also provides the voice for Gunther in the animated series Jane and the Dragon and Eddie in Marvin The Tap-Dancing Horse, as well as various characters in Little Bear, Redwall, Mythic Warriors: Guardians of the Legend, Tales from the Cryptkeeper, Timothy Goes to School, Babar: King of the Elephants, and Bad Dog.
In 2005, Reid played the role of Darrell Fox in the made-for-television movie Terry which dramatized Terry Fox's historic run for cancer research. In 2007, he appeared in the Naturally, Sadie episode "As the Whirly Turns". In 2009, Reid guest-starred in the Degrassi: The Next Generation episode "Danger Zone".
Reid's first leading role in a feature film was Farley Gordon in Score: A Hockey Musical—which premiered at the 2010 Toronto International Film Festival. Following this, he played several guest roles on television, including in the police drama Rookie Blue (2012) and the drama series Cracked (2013). In 2013, he also appeared in the CW web series Backpackers. In 2015, he played the lead role in the ABC comedy series Kevin From Work. The series was canceled by ABC after one season.
In 2016, Reid was nominated for a Canadian Screen Award for Best Original Song for his work in the feature film People Hold On (2015), in which he also starred. In 2017, Reid played the recurring role of Patrick in the third season of the CBC series Schitt's Creek. That year, he was also cast in the independent film Cardinals, opposite Sheila McCarthy, which premiered at the 2017 Toronto International Film Festival.
In 2018, he reprised his role in the fourth season of Schitt's Creek, and performed in a production of Hamlet at the Tarragon Theatre in Toronto.
