He then returned to Australia on a QEII Fellowship at the Australian National University, and undertook research on applications of population viability analysis to conservation biology.

[4] In 2000 Possingham moved to a chair in the departments of Mathematics and Biological Sciences at the University of Queensland in Brisbane, where he was an ARC Professorial, Federation, and Laureate Fellow.

[7] In September 2020 he was appointed the Queensland Chief Scientist[8] During his academic career, Possingham has published over 650 peer-reviewed papers, and supervised 135 doctoral and postdoctoral researchers.

[9] It has been used to plan terrestrial and marine protected area networks for 5% of the Earth's surface, including Australia's Great Barrier Reef.

[16] In 2009 he proposed devoting a proportionate fraction of gambling revenues to saving an endangered species, to be selected by a random drawing shown on television before the Melbourne Cup.