John Ledger completed a B.Sc. Honours degree in Zoology at the University of the Witwatersrand in 1965 and thereafter worked at the South African Institute for Medical Research as a research scientist in the Department of Medical Entomology.
He spent 18 years at the SAIMR, completing his Doctorate at the School of Pathology and becoming Head of Department.
In 1985 John was appointed as Director of the Endangered Wildlife Trust. He grew this organization from 3 people to one of the leading conservation NGOs in Southern Africa.
He retired in 2002 to pursue his numerous other interests. He still edits the EWT's Vision magazine and its Vision annual book. He is Content Editor of African Wildlife, the journal of the Wildlife and Environment Society of South Africa.
John is Chairperson of the Sustainable Energy Society of Southern Africa (SESSA) and has business interests in solar water heating (see http://on-sunsolar.com/). He is a Non-Executive Director on the Board of the Johannesburg Zoo, a member of the Panel of Environmental Experts for the Lesotho Highlands Water Project, a Consultant to the Lesotho Biodiversity Trust and a member of the Advisory Board of the Mazda Wildlife Fund since it was launched in 1990. He is a Visiting Associate Professor at Wits University and lectures on renewable energy and energy efficiency for the M.Sc course in Environmental Science.