Denis Theriault was born in New Brunswick, Canada, discovering early on that he wanted to work in the entertainment industry. At age 14, he landed his first big TV role as Jeb in The Space Channel's hit science fiction series Starhunter.

Since then, Denis has appeared in various film and television projects. He is most recognized for his role in the feature film All the Wrong Reasons, starring alongside the late Cory Monteith, which had its world premiere at the 2013 Toronto International Film Festival. The role earned him an ACTRA Maritimes Award nomination for Outstanding Male Performance. His work can also be seen in the feature film Growing Op, on CityTV/CW's Seed, Showcase's G-Spot and HBO's Call Me Fitz. His latest film Across the Line is the racially charged feature debut of acclaimed music video director, Director X. The role of Todd, the story's main antagonist, once again earned Theriault an ACTRA Maritimes Award nomination for Outstanding Male Actor in a Supporting Role.