This study delves into the transformative impact of a professional development model (PDM) across three affiliated private schools in Beirut, Lebanon, spanning three years, with a primary focus on nurturing teacher leadership. At the heart of this PDM, teachers assumed the role of trainers, guiding their colleagues during dedicated professional development days. Employing a grounded theory approach, the study conducted semi-structured interviews with 12 teacher trainers and engaged with three school principals. The research reveals five central categories. Two categories revolve around the evidence highlighting the progression of teacher leadership: (1) accessing and utilising research to enhance teaching and student learning, and (2) promoting professional learning for continuous improvement. Additionally, three categories elucidate the elements instrumental in facilitating the PDM's role in cultivating teacher leadership: reciprocal empowerment, conceptual awareness, and collaborative metacognition. This model redefines traditional top-down leadership structures, allowing teachers to actively mold their professional development journey, creating a more collaborative and intentional approach to teacher leadership.