The necessity for the development and enhancement of teacher commitment to satisfying students' learning needs in response to the COVID crisis is increasingly highlighted. It is not known, however, how to increase commitment in schoolteachers to boost online teaching in light of the fact that they, too, are struggling to cope with the rapid, unexpected change. A total of 601 teachers from primary and secondary schools across China participated in this study, with an average teaching experience of 15.9 years. Structural equation modelling was used to verify the significance of contextual, cognitive, affective and behavioural factors in boosting teachers' commitment to online teaching. The findings demonstrated that teacher agency played a complete mediating role in the predicting power of other factors to teacher commitment. Therefore, it was recommended that attention be paid to the practice and opportunities for teacher agentic actions, which necessitates real encounters with online teaching, allowing teachers to act meaningfully and initiate a new set of teaching strategies.