This study examines the historical evolution of the Korean Society of Applied Zoology (KSAZ) from 1957 to 1962, focusing on its pivotal role in developing a distinctive developmentalist conservationism in postwar South Korea. Established under Kim Hon-kyu’s leadership, KSAZ explicitly distanced itself from ‘pure’ biology to prioritize the ‘request of the times’—specifically, increasing agricultural productivity and resolving public health crises through the control of pests and rodents. Supported by continuous funding from the Asia Foundation, KSAZ conducted extensive academic expeditions to Jeju Island, Mt. Seorak, and Mt. Jiri, frequently collaborating with U.S. military entomologists to study disease vectors in post-conflict environments. A significant shift occurred after the 1960 International Council for Bird Preservation (ICBP) meeting in Tokyo. Figures such as Won Pyong-oh reframed bird protection not as a sentimental endeavor but as a scientific method of resource management and biological control against forest pests like the pine moth. This utilitarian logic allowed conservation to be seamlessly integrated into the Park Chung-hee regime’s developmentalist agenda, leading to the designation of Mt. Jiri as the nation’s first national park. Ultimately, KSAZ provided the epistemic foundation for the state-led nature protection movements of the 1970s.