Professor Marshall was awarded a Bachelor of Science with 1st Class Honours in zoology from the University of St Andrews, Scotland in 1985. He completed a Doctor of Philosophy in Neurobiology in 1991 at the University of Sussex, Brighton, researching vision in mantis shrimps.
Professor Marshall continued at the University of Sussex until 1996, when he took up a position in the Vision Touch and Hearing Research Centre within the School of Biomedical Sciences at The University of Queensland. He was recruited to the Queensland Brain Institute in 2010.
The recipient of many grants and awards, most recently in 2011 Professor Marshall was awarded The University of Queensland Vice-Chancellor's Senior Research Fellowship and in 2014 he was awarded an Australian Research Council Laureate Fellowship. His research is funded by the Australian and United States funding agencies.
Professor Marshall's principle aim is to understand how other animals perceive their environment. As arrogant humans we tend to assume we are the pinnacle of evolution, however, certainly in sensory terms this is far from true. By taking an approach to sensory systems which is based around ecology but also includes physiology, anatomy, behaviour and neural integration, he hopes to decode languages such as colour and polarisation. Much of his work focusses on the marine environment, in particular reef systems and the deep-sea. As part of this effort he has become acutely aware of man's influence on both these environments and now run two projects / organisations: The Deep Australia Project, bringing research submersibles and high-tech deep-sea capability to Australia for the first time and CoralWatch, the world's largest citizen-science-based coral health assessment program (60 countries, 10 languages).