Katharine Isabelle was born Katharine Isobel Murray in Vancouver, British Columbia, to Graeme Murray, an Emmy Award-winning art director and production designer, and Gail Murray, an amateur writer and producer. She is the sister of journalist and former child actor Joshua Murray.
Isabelle began her acting career in 1989 with roles in films such as Cousins, Cold Front, and The Madonna episode of MacGyver. She quickly proved herself as a skilled actress, taking on more significant roles in films like Knight Moves and Disturbing Behavior.
In 2000, Isabelle landed the lead role in the cult-favorite film Ginger Snaps, which cemented her status as a talented actress. She went on to appear in a range of films, including horror and slasher movies like Carrie, Freddy vs. Jason, and the Ginger Snaps sequels.
In addition to her film work, Isabelle has also appeared in numerous television shows, including The X-Files, Da Vinci's Inquest, Smallville, and Supernatural. Her guest roles have been well-received, and she has received several award nominations for her performances.
Isabelle has also ventured into independent films, starring in projects like Falling Angels, On the Corner, and Frankie & Alice. She received a Gemini Award for Best Performance by an Actress in a Featured Supporting Role in a Dramatic Program or Mini-Series for her role in The Englishman's Boy.
In 2012, Isabelle starred in the horror film American Mary, which earned her several award nominations and wins, including the Festival Trophy Award for Best Actress. She went on to appear in films like 13 Eerie, Torment, and Lawrence & Holloman, and received a Leo Award nomination for her performance in the latter.
Isabelle also had a recurring role as Margot Verger in the NBC TV series Hannibal, and reunited with the creators of American Mary in the film See No Evil 2. In 2015, she starred in the thriller film 88, the horror film The Girl in the Photographs, and the indie film How to Plan an Orgy in a Small Town.