Teacher innovation is closely related to the improvement of basic education quality, and the cultivation of innovative talent for the nation. However, few studies have employed the causes of teacher innovation from the perspective of intrinsic motivation. To explore the factors and mechanisms affecting teacher innovation, we surveyed 421 middle school teachers to investigate the mediating roles of organizational identification and work engagement in the relationship between career calling and teacher innovation. The results indicate that career calling has a significantly positive impact on teacher innovation and that both organizational identification and work engagement mediate the effect of career calling on teacher innovation. Moreover, organizational identification and work engagement act as chain mediators in the relationship between career calling and teacher innovation. Therefore, to promote teacher innovation in middle school, it is important to emphasize the sense of calling, organizational identification, and work engagement. Practical implications for how to promote teacher innovation are also discussed.