Gallagher holds an MA in Creative Writing (Research) from the University of Melbourne, and has studied for a PhD in English Literary studies at the same university.
Her plays include Web (LaMama 1995, Junction Theatre 1996), Banshee (LaMama 1996), Elegy (Playbox, 2000), and Victory Girls (LaMama 2000). She has also written a libretto for Oz Opera, Remembering Rosie (2001).
Gallagher has published short stories and academic papers. Her current research focuses on the embodiment of the witch in the seventeenth and nineteenth centuries, and the ways in which the nineteenth century reinvents occult and supernatural discourse in fictional and scientific terms.