Denis is an Emeritus Professor and former Dean of Education of the University of Canberra. He has been involved in many national and international activities in science education. In 1998 he was a visiting scholar at the National Research Council in Washington DC working on a project examining inquiry and the National Science Education Standards. He is presently Chair of the ACT Teacher Quality Institute
National projects for which Denis has been responsible include:
- Primary Investigations – a curriculum resource for primary schools with an associated professional learning model
- Status and Quality of Teaching and Learning of Science in Australian Schools
- Collaborative Australian Secondary Science Project (CASSP) that evaluated a teacher change model through the development of integrated curriculum and professional development resources.
- Science by Doing – concept plan 2006 and Stage One 2009-11
- Australian School Science Education: National Action Plan 2008–12
- National Science Curriculum Framing Paper 2008