Mr Er brings extensive experience in strategic planning and sustainable development, demonstrated through his transformative leadership at various public agencies. Prior to his current appointments, he was Deputy Secretary (Planning), Ministry of National Development, where he oversaw land use planning, infrastructure, as well as research and development issues. As Chief Executive Officer, National Parks Board between 2014 and 2023, he led the development of Singapore’s City in Nature vision, which is part of the Singapore Green Plan 2030. Under his leadership, the Singapore Botanic Gardens was inscribed as a UNESCO World Heritage Site and new island-wide green networks and connections such as the Nature Park Network, Coast to Coast and Round Island Routes were established, offering Singaporeans access to even more green spaces. Mr Er currently serves on the board of Temasek Life Sciences Laboratory Limited. He was formerly a member of the Land Transport Authority and National Parks Board. He was awarded The Public Administration Medal (Gold) in 2023.

Mr Er graduated with a Bachelor of Science (Forestry), first class honours, from the Australian National University in 1996. He pursued a postgraduate programme at the University of British Columbia and graduated with a Master of Science in 2002. He has undertaken research in urban ecology, conservation biology, avian ecology and wildlife management.