With the recent curriculum reform in basic education (elementary to senior high school) in the Philippines, developing the research capacity of teachers is seen as a key factor in enhancing their instructional practices. The professional development (PD) design which was the data source of this qualitative study was conceptualised to follow a sustainable research and school-based model. The PD model had two phases, each incorporating collaborative and reflective components where the teachers were scaffolded by university-based science education specialists, who acted as both collaborators and experts in the processes of reflection and sense-making the impacts of the PD. Phase 1 was the five-day seminar-workshop whose main output was a collaboratively-planned and constructed, tried out, presented, observed, critiqued, and reflected inquiry-based lesson from each of the six Grade level teams (five teachers in each team from Grades 1-6) of elementary school science teachers. Phase 2 was the follow-up comprising school visits for lesson observation, collaborative reflection, and constructive critiquing of the research lessons. From collaborative reflections, findings revealed that teachers regarded their PD as a simultaneous social and cognitive process of adult learning, a venue for shared ownership which yielded commitment towards enacted practices, and an experiential learning environment with the provision for suitable prompts for reflective practice. It further created their sense of professional identity as they established a shared leadership and feeling of effectiveness and improved sense of teacher identity.