He studied theoretical physics and aeronautical engineering but eventually decided to become an actor instead, and enrolled in the National Theatre School of Canada.
Fiorini was a stage actor in Canada and London, before returning country of birth to try his hand at Italian films.
In 1968, he co-starred in the crime film Roma come Chicago, opposite John Cassavetes and Gabriele Ferzetti.
He lived for several years in Italy where he appeared in genre films, sometimes using aliases such as Ludovico Svengali, Matt Silence, Mark Farran and Ashborn Hamilton Jr.
He played the Werewolf Syndicate Leader in the Canadian television series Big Wolf on Campus (1999-2002) and Cardinal Baggia in Angels & Demons (2009).