 Before working at Griffith University, Dewar taught at the universities of Lancaster and Warwick in the United Kingdom and was a fellow and tutor in law at Hertford College, Oxford.He was Head of Education and Training for Allen & Overy (London) from 1988-90

Dewar moved from the United Kingdom in 1995 to take up a professorial position in the Griffith Law School, where he eventually became the Dean of the Griffith Law School from 1999 to 2002.From 2002 to 2005, he was the Pro Vice-Chancellor for Business and Law and then became deputy vice-chancellor (academic).