This study aims to explore: 1) the profile of certified English teachers with good CMSE, 2) teachers’ perception of PPG programs, 3) teachers’ experiences in PPG, and 4) how the teachers’ perception of CMSE is reflected in the classroom practice. This study also adopted the CMSE scale developed by Salter and Main (2020). The present study used a case study approach, and a questionnaire to collect the data, and validated through an in-depth interview and observation. The data was analyzed using an interactive model.

The findings revealed that: 1) the profile of certified English teachers with good CMSE was perseverant, highly motivated, and sociable, 2) the teachers perceived the PPG Program provided activities to develop classroom management self-efficacy, 3) through experiences by themselves, seeing other experiences, other's advice, and their emotional arousal during PPG increase not only knowledge and skill but also CMSE, and 4) teachers’ perceptions of CMSE are reflected in their classroom management, which includes controlling student behavior, developing instructional strategies, and communicating with students. The present study suggests that professional development can improve someone's self-efficacy including in conducting classroom management. Therefore, participating in a professional development program is suggested for the teachers to keep and increase their CMSE.