Benjamin has a civil engineering degree from Sydney University and worked in the land development industry, both in Australia and South East Asia since 1968, having immigrated to Australia from Hong Kong in 1962.
He chaired the Council for Multicultural Australia which assists the Australian Government to implement its multicultural policies. He is the deputy chairman of NSW Government Multicultural Business Advisory Panel, president of Sydney University Nerve Research Foundation, a director of Chain Reaction Foundation and an honorary governor to the Council of Sydney Medical School Foundation, University of Sydney. He also served six years on the Council of the National Museum of Australia as well as at Bond University.
Over the past thirty years, he has served as president for Australian Chinese Charity Foundation, Australian Chinese Community Association and Chinese Australian Forum of NSW and played other key roles in the management committee.
He was awarded a Centenary Medal in 2001 and an Officer of the Order of Australia in 2007.