Decades of research have amassed knowledge on the intricacies of reading and the necessity for systematic efforts in the classroom to foster comprehension skills. Conversely, studies on reader training practices in classrooms caution about the disparities with reading science proposals and the intricacies of enhancing pedagogical practices in regular and large classrooms where reading is pursued for learning. The applied instructional study contributes a methodology for the professional development of the regulatory mediation capacity in joint readings within the classroom through an online training program involving 22 teachers working in 3rd grade. The participatory research methodology involved 10 cycles of Ecological Classroom Study with teleconferenced collective counseling sessions using the debriefing technique with a writing tool to consolidate critical reflections and define progress goals. The results demonstrate sustained and significant improvement in the regulation of reading activities in the classroom, transitioning from a focus on extrinsic motivation and assessment to an emphasis on external regulation and the task of reading with learners. Additionally, there was profound progress in the theoretical underpinnings of action. The program's effects are discussed in relation to the training model and its implementation characteristics.