Teachers’ emotions are the product of the interaction between individual characteristics and the external environment. Using educational ecology theory as a framework, this study explores the emotions of secondary school German teachers. By analyzing the complex and variable external environments and teachers’ emotional experiences at different levels within the educational ecological system, the study found that teachers’ positive emotional experiences mainly stem from harmonious colleague and teacher-student relationships and successful teaching practices. Negative emotional experiences are primarily centered on tasks with weak relevance to teaching and a lack of understanding from outsiders. Additionally, due to the relatively weak foundation, the development of the German subject and teachers’ emotions are more susceptible to the influence of policy orientation, local educational research institutions, and various levels within the ecological system.