He attended Etobicoke School of the Arts in Toronto,[2] Sheridan College in Oakville,[3] and was a member of the inaugural season of the Birmingham Conservatory for Classical Theatre Training in Stratford, Ontario.

[8] While on Broadway in a revival of Fiddler on the Roof, Therriault got news that he had secured the role of Gollum in the Toronto premiere of The Lord of the Rings: The Musical.

[10] When it closed, he returned to Saskatchewan to film the made-for-television adaptation of Guy Vanderhaeghe's The Englishman's Boy (it aired in two parts on March 2 and 9, 2008, and is now available on DVD).

[11] On Monday, October 20, 2008, Therriault took part in a tribute to the late Richard Monette, former artistic director of the Stratford Shakespeare Festival.

[13] On April 27, 2009, it was announced that Therriault will appear as Irving Berlin, alongside Michael Boatman as Scott Joplin, in The Tin Pan Alley Rag,[14] which centers around the imagined meeting of the two great musicians.