Hiew graduated from Kagoshima University, Japan, in Fisheries Management. He started his career as a Fisheries Officer with the Department of Fisheries, Malaysia in 1973. Hiew  was the State Fisheries Director for Melaka and Negeri Sembilan from 1989 – 1992, and for Johor from 1992 – 1994. Hiew was later appointed as the Head of Marine Park Division from 1994 and was in charge of conservation and protection of marine habitats and species, including sea turtles. Hiew retired from government service in 2001. His contribution to conservation continued after retirement when he joined WWF-Malaysia from 2001 – 2014 where he was mostly responsible for marine conservation, fisheries resources management and also conservation and protection of marine species, especially sea turtles. For all his hard work and dedication, Hiew received the Edward T LaRoe III Memorial Award at the 2019 International Congress for Conservation Biology in Kuala Lumpur. In 2010, he was awarded the WWF International Award for Conservation Merit for his commitment to conservation of marine species and habitats in Malaysia and around the region. He also received an award from by WWF-Philippines in 2000 for his work on sea turtles. Hiew is also a Trustee in the Board of Trustees of Reef Check Malaysia, an NGO working on Conservation of Marine Habitats.