Teacher job satisfaction has been investigated as a critical influence on teacher turnout and the development of high-quality schools. Employing hierarchical linear modeling (HLM), the present study examined the effects of both teacher- and school-level factors on teacher job satisfaction in Japan and South Korea. Education in both countries is rooted in an East Asian cultural setting, and a comparison across the two countries will contribute to the discovery of underlying factors that affect teacher job satisfaction. The current study, based on the 2018 Teaching and Learning International Survey, showed that gender, teaching experience, social utility motivation to teach, self-efficacy, teacher-student relations, professional development, and team innovativeness exerted a crucial influence on teacher job satisfaction at teacher-level for Japan and South Korea. Furthermore, school sector, school delinquency and violence, and lack of special needs personnel were distinctive factors at school-level related to teacher job satisfaction for the two countries. The findings were discussed within the East Asian cultural context as well as comparatively, regarding East Asian versus Western cultures.