Between 1993 and 1997, Hossack served as the Australian cultural attaché in London. She is on the board of LAPADA (the Association of Art and Antiques Dealers) and of Resurgence (the influential periodical of alternative thought). She writes regularly in the national press and lectures internationally on Aboriginal Art, contributing articles to both the Macmillan Dictionary of Art (1996) and the Oxford History of Western Art (2000). Hossack also curates the calendar of exhibitions at Anthropologie in the UK and has 20 pop-up galleries in Gail’s Bakeries around London.
Hossack is a dedicated campaigner for environmental issues. In 2006, she was elected as Councillor for the Bloomsbury Ward in Camden. The following year, she ran the New York Marathon, raising over £20,000 to plant trees in central London. She works extensively on the Burrup peninsular in Western Australia, where she assists with the preservation of rock art.