Background: The district is an important strategic point in the development of the health system based on the concept of area-based and people centred. It is consistent with the principles of Primary Health Care (PHC) in the Alma Ata Declaration 1978 and the Astana Declaration 2018. Key components of PHC include people-centered services delivery of essential primary health care, multi-sectoral policy and actions, and empowering people and community for self-care. District Health Board (DHB) or “Por Chor Or” (in Thai) is a model and mechanism that expedites health and improves quality of life of local people. The mechanism was initially introduced as a few pilot districts in B.E. 2558. Later, in B.E. 2559 and B.E. 2560, participating districts were increased to 73 and 200 districts respectively. In B.E. 2562, this management model was implemented nationwide. This study aims to assess how Por Chor Or is implemented in different districts and whether it follows the IPCHS concept as well as propose policy recommendations for future development. Method: The study employed mixed-method study design. Purposive sampling was used for selection of study areas in 8 provinces including Chumporn, Nakhon Panom, Nakhon Sawan, Nan, Ratchaburi, Srisaket, Songkla, and Saraburi. Three districts categorized in each province were selected according to a suggestion from responsible health officers at provincial level who categorized each of the proposed districts into three implementation levels: ‘good’, ‘moderate’, and ‘initiating’. For qualitative research, in-depth and focus group interviews were conducted with 891 participants using semi-structured interview guidelines. Thematic analysis was used for qualitative data analysis. For quantitative research, 8,562 participants answered online questionnaire adapted from WHOQOLBREF. One-way ANOVA was used for quantitative data analysis on SPSS. Results: Qualitative data analysis showed that Por Chor Ors in ‘good’ and ‘moderate’ implementation levels demonstrated learning organization features including building multi-sectoral collaboration, shared ownership, and co-implementation of Por Chor Or’s policy. In terms of working process, ‘good’ and ‘moderate’ Por Chor Ors emphasized on informal monitoring, regular and two way communication, and creating structures or bodies that linked policy implementation from subdistrict to village level. They also had integrated health services that shared Por Chor Or’s policy emphasis including focuses on health promotion and disease prevention as well as enhancing quality of life. This work had been implemented through Sub-district committee on quality of life improvement or “Por Chor Tor” (in Thai), a sub-district mechanism for Por Chor Or’s policy implementation. Also, leadership to implement the policy was stronger in other sectors outside public health. Locals in ‘good’ and ‘moderate’ Por Chor Ors also had better perception and participation in health development and quality improvement related activities. For ‘initiating’ Por Chor Ors, they relied on bureaucratic working system to implement Por Chor Or’s policy. Multisectoral collaboration and co-ownership of Por Chor Or’s policy implementation was scarce or unclear. Public health sector remained leading sector in policy implementation. However, public health services were shifting towards health promotion and disease prevention in ‘developing’ Por Chor Ors and locals had minimal perception and participation in health development and quality of life related activities. Quantitative findings showed that overall quality of life score was the highest in ‘good’ Por Chor Ors (97.1, S.D. 11.1); followed by ‘initiating’ Por Chor Ors (96.0, S.D. 11.8) and ‘moderate’ Por Chor Ors (95.8, S.D. 10.6) respectively. Enhancing factors for Por Chor Or’s success included competency and leadership of District Chiefs and Por Chor Or’s secretary teams, particularly for District Health Officer, multi-sectoral participation, clear working structures that linked policy implementation between district and sub-district levels, supports from provincial administrative bodies, and visits from provincial and regional health bodies to empower Por Chor Ors. Additionally, the study showed that using UCCARE for Por Chor Or evaluation might not accurately reflect the mechanism’s level of implementation or development due to ambiguity of criteria interpretation of UCCARE by the stakeholders. Conclusion: District Health Board or Por Chor Or is a mechanism that encourages multi-sectoral and local individual collaboration to empower health management and self-care that leads to an improvement of individual’s quality of life. The success of Por Chor Ors comes from integration of bureaucratic administration and ‘bottom-up’ approaches which can explore and respond to people’s health needs. The change is galvanized by District Chiefs and other stakeholders whose leadership and understanding of local needs can support a work culture of learning organization. All Por Chor Ors work in consistent with policy and health system development which is based on primary health care principle and concept. Further improvement of system and tools to support Por Chor Ors needs to align with capacity, amount, difficulties, and strategic issues of each Por Chor besides having existing tools for self-assessment. The success of implementing those tools will result in more effective strategy formulation and better development for Por Chor Ors.