Inga Simpson was raised in central west NSW, and has lived in Canberra, Brisbane, and the Sunshine Coast hinterland: in 2018, she was based on the far south coast of NSW. Before beginning her writing career, she worked as a professional writer and researcher in government and public service, including for the Commonwealth Ombudsman.
Simpson holds a masters in Australian literature from the University of New South Wales and two PhDs: the first in creative writing from the Queensland University of Technology (QUT, conferred 2008) and the second in English literature from The University of Queensland (conferred 2017). Her creative-writing dissertation explored literary lesbian detective fiction, particularly in Australian writing, and included her detective novel 'Fatal Development'. Her English literature dissertation explored Australian nature writing. She subsequently published her first work of nature writing, Understory, in 2017: it was shortlisted for the Adelaide Festival Awards for Literature.
The manuscript for the thriller Off the Grid was shortlisted for the Queensland Premier's Literary Awards (best manuscript by an emerging Queensland writer) in 2009, but Simpson's first novel, Mr Wigg, appeared in 2013. Since then, her novels have attracted nominations for such awards as the Miles Franklin Award, the Stella Prize, and the ALS Gold Medal.