Gillian Horgan was born in Ireland and educated at Trinity College, Dublin (BA, MA in Natural Sciences). She worked as a research microbiologist at two London University teaching hospitals and at Yale University before moving to New York, where she worked for a global pharmaceutical company, was a fundraiser for a non-profit organization, and a technical writer at the 12th largest bank in the U.S.

Since 1985, living in Glengarry County, Eastern Ontario, she worked for over 20 years as a software documentation architect and writer consultant for multi-national telecommunications companies in Montreal, Quebec. After taking photographs for many years, she became a professional art photographer in 2006.

The first show of her photographic work was the 2007 One of a Kind Spring Show, in Toronto. Her work has also been shown at Fine Arts Shows at the Abbey for the Arts, Glen Nevis; PhotoLab, galleryDK,  Toronto;  Art Expo Ottawa; and solo shows at Galerie Ouest, Solo Show, St. Anne-de-Bellevue, Quebec. She has also exhibited at many Art in the Park shows in Ontario.