Despite the crucial importance of teacher impact for a wide range of student and teacher outcomes, it is not clear whether any individual-level factors precede teacher passion and if so how. Drawing on self-regulation theory and the self-regulatory strength model, I propose a theoretical reciprocal model in which teachers' sleep quality predicts their work enjoyment and engagement in cooperative interaction with others in school, both of which lead to greater work passion. In turn, higher levels of work passion have a reciprocal effect on the teachers' sleep quality. The model is tested using experience sampling method (ESM) data collected from 137 teacher leaders in Hong Kong and 79 teacher leaders in Shanghai. Teacher leaders responded to short ESM questionnaires three times a day for ten consecutive working days. The results of cross-lagged path analysis support the hypothetical model. The results are interpreted as that nurturing teacher passion is partly a within-person process; teachers' passion can stem from their own work enjoyment and positive interaction with others in schools, for both of which good quality sleep is helpful.