Background: The primary school age group (aged 5-11 years) is acknowledged as a critical period in the development of physical activity patterns and healthy lifestyle behaviours. Furthermore, high quality physical education (PE) is crucial for the development of lifelong physical activity behaviours and is highly dependent on the interaction between the teacher and the pupil. Despite this, there is a lack of training and confidence of many primary generalist teachers to teach PE in the UK. It is argued that effective continuing professional development (CPD) to address this issue should be supportive, job embedded, instructionally focused, collaborative and ongoing. Purpose: This study was funded by a national government funded organisation and led by a university in collaboration with a secondary PE specialist and two primary teachers. The purpose was to develop a replicable PE-CPD process to improve primary generalist teachers' PE pedagogy by transferring their positive pedagogy from the classroom to the PE setting. Participants: The participants were two Year 3 (age 7-8 years) primary classroom teachers from the same school and one secondary PE specialist teacher who acted as a mentor. Research approach: A collaborative professional learning (CPL) approach was utilised to develop the PE-CPD intervention process. CPL involves teachers and other members of a profession working together to improve their own and others' learning on pedagogic issues. A six-week needs assessment phase was completed through classroom and PE lesson observations to identify key areas for development in the PE-CPD process over the duration of a 23 week intervention. Data collection and analysis: Reflective logs, structured lesson observations and teacher interviews were used to collect the data during the PE-CPD intervention. Inductive and deductive qualitative thematic analysis was used to analyse and interpret the data. Findings: A number of key themes were generated during the data analysis including the transfer of positive pedagogy from the classroom to the PE setting and the implementation of effective pedagogic principles including the setting of clear learning outcomes, differentiation and inclusion to enhance the PE pedagogy. A key element to the success of the intervention was the trusting relationships built by the secondary PE specialist with the primary teachers. Further, the results also revealed the importance of CPL in ensuring rigorous, evidence-based PE-CPD and providing the time and support required for fundamental sustainable changes in practice, which can endure beyond the life of the research project. Conclusion: The major contribution of this paper is in demonstrating the potential of CPL between national organisations, universities, secondary and primary schools to improve the PE pedagogy of primary generalist teachers. Future research should build upon the findings in this study and replicate this PE-CPD approach with other classes and schools.