Sigismondi was born in Pescara, Pescara, Italy. Her parents, Lina and Domenico Sigismondi, were opera Singers. Her family, including her sister Antonella, moved to Hamilton, Ontario, Canada when she was two. In her childhood she became obsessed by drawing and painting. Later, from 1987 she studied painting and illustration at the Ontario College of Art, today's Ontario College of Art & Design University (OCADU). When she took a photography course, she became obsessed once more, and graduated with a photography major.