Denis was born and educated in Sydney. He worked in the public sector for most of his career and studied Public Administration at the NSW Institute of Technology.
The first half of his career was spent in auditing (both internal and external) followed by a move to the Australian Broadcasting Tribunal. His role included managing a database of financial data provided by the broadcasters and producing statistics on the broadcasting sector and viability studies into the capacity of markets to support new services.
In later years, he commenced a small computer accounting and bookkeeping consultancy. He moved to Nelson Bay 11 years ago and has an interest in maintaining and sustaining the ecological beauty of the area.