Implementation of Education for Sustainable Development is a complex social phenomenon. This research aims to suggest ways to strengthen the implementation of ESD, identifying the factors affecting pre-service teachers' intention of implementing ESD. To this end, the author focused on revealing the different combinations of conditions predicting Korean pre-service teachers' intention to implementing education for sustainable development (ESD). The research method is the fuzzy sets qualitative comparative analysis (fsQCA) using the set-theoretic relations, starting from the premise that social phenomena have causal complexity characteristics. An analysis of 245 valid questionnaires from Korean pre-service teachers resulted in three main findings. The author suggested that teacher education institutions need to include content related to ESD in the teacher education curriculum so that pre-service teachers can cultivate positive attitudes toward ESD and improve their self-efficacy in student engagement and instruction in the context of ESD. [This paper was presented at the 7th International Conference on Lifelong Education and Leadership for All (ICLEL).]