He took time out from his scientific career to serve as the 28th Governor of Victoria from 2006 to 2011 during which he managed to find small amounts of time to keep up his research interests.

Since April 2011 David has resumed research at Monash University working at the MIMR-PHI Institute of Medical Rsearch (formerly Monash Institute of Medical Research), based at the Monash Medical Centre and also in the Department of Anatomy and Developmental Biology on the Clayton Campus of Monash.

Throughout his career David has practised as an endocrinologist with a major focus on male reproductive disorders. He believes that patients provide the triggers for research and, while some of his work is basic and molecular, there is always a translational aim. Being an experienced microscopist using both light and electron microscopes, he always tries to link structure with function.

His research programs address the causes and management of male infertility and included the development, with his colleagues, of a collection of DNA samples from men with infertility to enable the identification of new genetic causes of male infertility. These studies include the use of random mutagenesis in mice to identify genes causing spermatogenic disorders. 

His work on the hormonal regulation of reproduction identified inhibin and follistatin as novel proteins controlling FSH secretion. This work has led to a change in direction of some of his work since the activins, which raise FSH and are modulated by follistatin, turn out to be major regulators of the inflammatory and fibrotic responses. A significant part of his work today is involved in further characterising diagnostic and therapeutic applications of the activins and follistatin.

David is also a passionate advocate for the need to undertake preventive action to improve male health. For the past 12 years, with support form the Federal Government, he initiated, with colleagues from around Australia, a highly successful program of community and professional education in male reproductive health called Andrology Australia.

Throughout his career, David has built lasting collaborative programs in research with colleagues locally, nationally and internationally, recognizing that research today requires a multiplicity of technologies that are only available through research teams and not found in one person.