Denis graduated from Melbourne University in 1975 with BA and LLB degrees. He was later awarded an LLM degree from the ANU for his thesis dealing with the Governor-General’s powers to dissolve the Houses of Parliament. Before joining Minter Ellison in 1989, Denis was a Senior Executive lawyer in the Commonwealth Attorney-General’s Department. His practice as a partner in Minter Ellison was mainly in the area of administrative law, covering both judicial and tribunal review. He drafted Fiji’s 1997 Constitution. Denis was the head of the Refugee and Migration Review Tribunals from 2007 to 2012.