Introduction: Physical activity (PA) levels in children are below recommended guidelines and are declining throughout adolescence, threatening negative consequences such as obesity, heart disease, stroke and type II diabetes to the current and future health of Irish young people. Physical Education (PE) is provided to promote PA to school-going students and to enable them to pursue healthy and active lives. The World Health Organization (WHO) recommends school-based interventions to assist the promotion of PA among young people. Purpose: The purpose of this research was to trial, refine and extend the PE element of the Y-PATH programme in line with national curricular developments, based on the thoughts and opinions of students and specialist PE teachers in Irish post-primary schools. Methods: Following the completion of a 12-week intervention of the Y-PATH PE programme in Irish post-primary schools (N=9), cross-sectional data were collected from participating students (N=317) using questionnaires, in order to investigate students’ PA levels, physical self-worth, enjoyment and experiences of PE. Additionally, all students were afforded the opportunity to express their thoughts and opinions using open-ended questions. Focus group and semi-structured interviews were conducted to gather data on the thoughts and opinions of participating PE teachers (N=15) on the programme and were analysed qualitatively using thematic analysis. Results: Following the intervention, repeated measures Analysis of Variance (ANOVA) tests revealed that students with higher levels of PA had higher self-worth, greater enjoyment of PE and more positive experiences in PE class in comparison to those students with lower levels of PA, all of which are central components of the Y-PATH PE programme. Findings from the teacher feedback revealed four main themes. These themes explored the usability of materials and resources, Y-PATH content suitability, implementation considerations and the current PE curricular context. Conclusion: Data collected indicated the majority of students who were involved in data collection had positive experiences participating in Y-PATH PE. Teacher feedback revealed the Y-PATH programme is suitable for students across single-gender and mixed gender schools, and across schools located both in urban and rural areas. Both student and teacher feedback provided valuable insight to the research team in relation to the use of the programme in the classroom, to guide the refinement and extension of the Y-PATH PE programme.