This study addresses the professional development of college English teachers in mainland China. It is designed to examine the relationship between teachers' motivation and their attitudinal elements including teacher engagement and commitment, and teaching approaches. This study adopts a mixed-method design that starts with a quantitative phase in which data were collected and analysed to examine the hypothesised predictive power of teachers' motivation on their engagement, commitment and teaching approaches. In the second phase, qualitative data acquired via semi-structured interviews and documentary analysis were collected to further interpret, explain and elaborate the quantitative results in greater depth. As language teaching has been an often-researched discipline in the teacher motivation literature, this study prompts one to rethink and reflect on the effectiveness of college English curriculum reform and provides implications for current college English teaching and the development of college English teachers.