Research on how pedagogical content knowledge (PCK)-informed faculty development initiatives can support PCK development among health professions educators is limited. Given the positive impact of PCK on enhancing professional knowledge for effective teaching, this study investigates the learning process of health professions educators in developing their PCK through a faculty development initiative, supported by the Content Representation (CoRe) tool. Using a qualitative approach, grounded in social constructionism, the study engaged eight educators from diverse health disciplines at an Australian university. Participants collaborated in developing and refining PCK-infused lesson plans using the CoRe tool. Several workshops, writing sessions, feedback sharing, and an online community of practice facilitated PCK-related discussion, resource sharing, and networking. Data collection comprised two rounds of individual interviews, written reflections, and lesson planning artefacts. Data were analysed using team-based thematic framework analysis. Four themes were identified: 1) articulating teaching purposes, (2) understanding students' learning needs, (3) promoting reflection on teaching practice, and (4) challenges in adapting and implementing the CoRe tool. The findings highlight the critical role of faculty development programs and advocate for the use of the CoRe tool for articulating and scaffolding PCK for both experienced and novice educators. The collaborative environment facilitated peer feedback and knowledge sharing, thus fostering a collective understanding of PCK and affirming its relevance within the broader health professions education community.