Denise began her working life as a synchronised swimmer. After academic study, she worked as head of the General Philosophy Department at University of Sydney, where she taught for 27 years. She wrote a book called, Women, Madness and Medicine another titled, Who Rules the Waves: piracy, overfishing and mining the oceans, founded a journal called Animal Issues and has written many papers about animal ethics. She is now a Research Fellow at the University of Wollongong and a supporter of the arts.