Mr Castleman has been Chairman of the Australian Centre for Health Research Limited since its inception in 2005. Mr Castleman has also been the Chairman of Australian Unity Limited since 1993 and is a director of a number of Australian Unity Limited subsidiaries. He was a director of the Monash Medical Centre from 1992 - 1994 and Chairman of the National Ageing Research Institute Inc for 6 years and a director for 10 years. He has also served as a member and chairman of CSIRO advisory boards. Before 1993, his executive career was at BHP where he held a number of senior executive positions. Over the last 18 years he has been Chairman or a director of over 15 public or private companies outside the Australian Unity Group.