Stevie Louise Vallance was born in Montreal, Canada, and raised in Toronto. She began her acting career at the age of 12, performing in the Charlottetown Festival's musical Jane Eyre. She then went on to appear in several Canadian television shows, including King of Kensington, The Wonder Of It All, and A Bird in the House.
After graduating from the American Academy of Dramatic Arts in New York, Vallance moved to Los Angeles, where she fronted a band and was discovered by CBS/Lorimar executive David Jacobs, who offered her a recurring role on the TV series Knots Landing. She then landed a regular role on The Ropers, alongside Norman Fell, Audra Lindley, and Jeffrey Tambor.
Over the next decade and a half, Vallance appeared in numerous TV shows and films, including Bosom Buddies, Lou Grant, L.A. Law, Road to Avonlea, and Slam Dunk Ernest. She also played roles in several action-adventure films, including Falcon's Gold/Robbers of the Sacred Mountain and Three Men & A Baby.
In the 1980s, Vallance commuted frequently between L.A. and Toronto, where she worked on several projects, including the late-night CBS series Night Heat and the Hallmark series Zoobilee Zoo. She also began to work increasingly in the animation voice-over field, becoming known as the "Cartoon Queen" for her prolific work on hundreds of productions.
Vallance's voice-over credits include roles in Reboot, Inspector Gadget, Thumbelina, Donkey Kong Country, Inuyasha, Sonic the Hedgehog, The Popples, Totally Spies!, Growing Up Creepie, and Bakugan Battle Brawlers. She has also received several awards and nominations for her work, including a Daytime Emmy Award for her direction of dialogue and vocals on the Disney classic The New Adventures of Madeline.
In addition to her voice-over work, Vallance has also become a sought-after cartoon voice-over coach, launching numerous voice-over careers through her Tooned In! Animation Acting Workshops. She has also taught voice-over workshops at the Ottawa International Animation Festival and New York's Comic Con.
Vallance has also pursued a career as a singer, releasing several jazz CDs, including "Practically Naked", "Always", and "Make My Night". She has also performed at several jazz festivals, including the Medicine Hat Jazz Festival and the Thornbury and Kincardine Jazz Festivals.
In recent years, Vallance has continued to work in the animation industry, serving as Voice Director on several projects, including Celebutard Nation, The Mysticons, and Norman Picklestripes. She has also written, directed, and performed in an original musical called "The Night Guy Came to Town", which premiered in 2023.