This study aimed to investigate how teacher preparation and professional experiential learning catalyze organizational and occupational commitment. Data from Taiwanese lower secondary school teachers who participated in the TALIS 2018 survey were analyzed using structural equation modeling, which yielded several key results. Firstly, both teacher preparedness and professional experiential learning had positive relationships with self-efficacy, with teacher preparedness showing a stronger association. Secondly, self-efficacy was more closely linked with organizational commitment than with occupational commitment. Thirdly, organizational commitment was positively associated with occupational commitment. Finally, both relationships of teacher preparedness and professional experiential learning with organizational commitment were partially mediated by self-efficacy, whereas full mediation was observed for occupational commitment. Notably, the most significant pathway in the mediation model was teacher preparedness predicting organizational commitment through teacher self-efficacy. These findings have implications for improving organizational commitment and promoting a positive outlook toward the teaching profession.