Became a professor and head of geology at the University of Newcastle through 1991. Plimer later served as professor and head of geology of the School of Earth Sciences at the University of Melbourne from 1991 to 2005. He was conferred as professor emeritus of earth sciences at the University of Melbourne in 2005, and was a professor of mining geology at the University of Adelaide. He is a member of the academic advisory council for the Global Warming Policy Foundation, a member of Australians for Northern Development & Economic Vision (ANDEV), and was an allied expert for the Natural Resources Stewardship Project. Plimer is a fellow of the Australian Academy of Technological Sciences and Engineering, the Australian Institute of Geoscientists and the Australasian Institute of Mining and Metallurgy; an honorary fellow of the Geological Society of London; a member of the Geological Society of Australia, the Royal Society of South Australia, the Royal Society of New South Wales and the Royal Society of Victoria. Plimer is the former non-executive director of CBH Resources Limited from 1998 to 2010, former non-executive director of Angel Mining plc from 2003 to 2005, former director of Kimberley Metals Limited from 2008 to 2009, former director of KBL Mining Limited from 2008 to 2009 and former director of Ormil Energy Limited from 2010 to 2011. He is currently the non-executive deputy chairman of KEFI Minerals since 2006, independent non-executive director of Ivanhoe Australia Limited since 2007, chairman of TNT Mines Limited since 2010, non-executive director of Niuminco Group Limited (formerly DSF International Holdings Limited) since 2011, and non-executive director of Silver City Minerals Limited since 2011. Plimer was appointed director of Roy Hill Holdings and Queensland Coal Investments in 2012. Plimer has stated that his business interests do not affect the independence of his beliefs. He has also warned that the proposed Australian carbon-trading scheme could decimate the Australian mining industry and written books and many articles supporting notions of climate denial.