Despite government efforts to reform teacher professional development (TPD) in the past four decades, Indonesian teacher quality remains low. Why have the improvement efforts failed? In the present study we investigate what caused these reforms to fail from two angles. First, we examine the efficacy of the latest teacher professional development (TPD) initiative in Indonesia, Pengembangan Keprofesian Berkelanjutan or PKB (Continuing Professional Development), and identify the factors affecting its efficacy. We found that some essential features of effective TPD are missing in PKB. The PKB programme has not targeted teachers based on years of experience, has not followed up teachers with post-training activities, has not incorporated teaching practice through lesson enactment, and has not built upon teacher existing practice. Second, our analysis demonstrates that PKB's weaknesses have existed in Indonesia's previous TPD initiatives as far back as four decades ago. This indicates that the long-term problem of TPD’s ineffectiveness is driven by different elements of the education system beyond the TPD’s technical and operational aspects. Our system-level analysis points out that merely improving the technical aspects of TPD would be insufficient given the Indonesian education system’s lack of coherence surrounding teacher quality. The problems surrounding the provision of effective TPD is more complex than simply a matter of replacing the “old” with the “new” initiative. The change requires a reorientation of the education system to produce high-quality teachers.