guarnieri was educated at mcgill university, where she graduated with a master's degree in english. as part of her thesis, she wrote a book called "the cheese on the moon: a collection of short stories". after graduating she worked for the federal government as a spokesperson for bob kaplan and also as a press liaison office for stuart smith, leader of the ontario liberal party. in 1981, she worked as an assistant to toronto mayor art eggleton but left after seven months "because of a disagreement". in 1984 she worked for "lowther consulting", a company owned by jim coutts who was a principal secretary for prime minister pierre trudeau. she and her husband live in mississauga.