Deborah Theaker was born in Moose Jaw, Saskatchewan but spent her formative years in Esterhazy, Saskatchewan, where her father served as the mayor and local mortician. She graduated from the University of Saskatchewan and relocated to Toronto where she became a member of Second City's resident Company.
Deb starred alongside Joe Flaherty in the Lucasfilm series Maniac Mansion. She also wrote for the series, a quirky satire about genetic mutation which was the brainchild of Eugene Levy and George Lucas.
Deb is a longtime collaborator of The Kids in the Hall. She co-wrote Scott Thompson's Comedy Central special and co-wrote and directed two solo stage shows for him.