Gemma Files was born in 1968 in London, England, the daughter of actors Elva Mai Hoover and Gary Files. Her family relocated to Toronto in 1969, where she resides today. Files graduated Ryerson Polytechnic University in 1991 with a degree in journalism; various freelance assignments eventually led to a continuing position with entertainment periodical eye Weekly (www.eye.net), where she gained local repute as an insightful commentator on the horror genre, independent films and Canadian cinema. She was listed by Cameron Bailey of NOW Magazine as one of the Top 10 Coolest People In Canadian Cinema for 1996. She has also written reviews for www.film.com and for the Canadian horror magazine Rue Morgue. In 2000 her award-winning story "The Emperor's Old Bones" was reprinted in The Year's Best Fantasy and Horror Thirteenth Annual Collection (ed. Terri Windling and Ellen Datlow). In 2010 her Shirley Jackson Award-nominated novelette "each thing i show you is a piece of my death" was reprinted in The Best Horror of the Year, Volume Two (ed. Ellen Datlow).

Files was married in 2002 to upcoming science-fiction and fantasy author Stephen J. Barringer (with whom she co-wrote "each thing i show you is a piece of my death"). They have one son, Callum Jacob, born in September 2004.

Files' protagonists tend to be self-willed outsiders and self-created monsters rather than "ordinary folks" or disposable victims -- people who are set apart from the normal "human" world by monstrous acts or monstrous natures, but accept their status without apology and endure the consequences as honestly as possible, rather than brooding over past sins and making half-hearted attempts at redemption. The morality of Files' universe does not exclude the possibility of goodness, hope, or love -- indeed, it is the awareness of loss of these things, and the desperate hunger to regain them, that drives much of her work -- but there is a very clear emphasis on personal responsibility. The worst fates met in Files' universe are typically reserved for those characters who attempt to deceive themselves, evade the consequences of their choices, or somehow cheat their way out of agreed bargains -- Regis Book of "Blood Makes Noise," who sacrifices everything to avoid the death he fears so much, and Rohise Gault of "Keepsake," who gives up her humanity in an attempt to keep the one thing she loves, are among the more memorable examples of this theme.

Many of Files' stories take classic horror tropes or images and put new spins of context or logical development upon them: the vampire protagonist of "Dead Bodies Possessed by Furious Motion" takes vampiric immortality and ennui to its logical extreme by stowing away on an interplanetary space probe, and the werewolf story of "At The Poor Girl Taken By Surprise" turns on a surprising but logical riff upon the cannibalism motifs underlying lycanthropy themes. Her cosmology is overtly supernatural -- featuring multiple breeds of vampire and shapeshifter as well as ghosts, psychic abilities ranging from mediumship to pyrokinesis, witchcraft and hermetic magic, cannibalistic life-extension, rogue angels and practicing exorcists -- but remains strongly focused on essentially human protagonists. One of her most powerful stories is "The Diarist" (which she self-adapted for The Hunger as above); in its original form, these last words of a jilted lover can be read either as an attempted witch's vendetta or as an entirely realistic tale of loss and heartbreak made even sadder by the impotence of its protagonist's "spells."