This research investigates the influence of the whole school approach (WSA) on the education for sustainable development (ESD) practices of teachers in Japan. We focus on understanding how school organizations that facilitate WSA influence teachers' ESD practices in a multifaceted and hierarchical manner. The multilevel analysis, which targeted 683 elementary and middle school teachers in ESD-promoting schools, revealed that the actual working environment may be more important than the school's management system for helping individual teachers implement ESD, and that school-level WSA made a clear contribution to promoting ESD. The research suggests the importance of establishing the environmental conditions, such as the school board and principals' guarantee of basic conditions (e.g., working hours, teaching materials, and an environment where teachers can exercise ownership), so that teachers who are interested in ESD practice can feel secure and assume ownership of ESD activities.