Doig's "exotic" appearance stems from her mixed heritage - Scottish on her father's side, Filipino on her mothers. She grew up in Toronto, Ontario. Inspired by the television series of her childhood, including Wonder Woman, Dukes of Hazzard and The A-Team, Doig dropped out of high school during her final year to pursue an acting career. She worked on stage productions of Romeo and Juliet and Arsenic and Old Lace while auditioning for film and television roles.
Her first significant role was on William Shatner's series TekWar. Doig recalls the time she heard the news of this role: "I walked out of the audition absolutely convinced I had blown it, and then my agent called to tell me I got the part. I was leaping around my parents' house and screaming at the top of my lungs. I knew then I'd chosen the right profession and I've never looked back since."
Doig landed the role of Tina Backus on the short-lived series CI5: The New Professionals in 1998, and finally burst into the spotlight with her role as the title character on the sci-fi series Andromeda. More recently, she has expanded into significant feature film roles, including the female lead in Jason X (2001).
Doig currently divides her time between her original home of Toronto and Vancouver, the center of the Canadian film industry. On 2 August 2003 she married fellow actor fellow actor Michael Shanks.