Implementing the Competency Profile-Based Professional Development Model (CPPDM): A Practical Guide for Pre- and In-Service English Teachers in Indonesia has been written as a practice-oriented extension of the dissertation Developing a Competency Profile-Based Professional Development Model for Pre-Service English Teachers Through Exploratory Practice in Indonesia. Its primary purpose is to bring the first author's dissertation theoretical and empirical insights into a form that is accessible, usable, and pedagogically meaningful for teachers and teacher educators. At the centre of this guide is a conviction that professional development should not be treated as something external to classroom life. Too often, teacher learning is framed as a separate activity, delivered through episodic training and later expected to transfer into practice. The CPPDM proposes a different orientation. Grounded in Exploratory Practice (Allwright, 1991), informed by the Genre-Based Teaching-Learning Cycle (Rothery, 1994; Derewianka, 2018), and supported by Halliday’s Systemic Functional Linguistics, the model positions the classroom itself as the primary site of professional inquiry, reflection, and growth. In this way, teaching becomes not only an instructional act, but also a disciplined process of noticing, interpreting, and refining practice