Ajahn Mun Bhūridatta and Ajahn Chah Subhaddo can be seen as shaping the Thai Forest Tradition in two successive movements: one establishing its inner core, the other extending its reach and clarifying its expression. Ajahn Mun revitalized Theravāda practice by returning to an austere, wilderness-based renunciate life, centered on strict adherence to the Vinaya and the traditional ascetic practices. Forests, mountains, and caves became not just backdrops but essential supports for intensive meditation and contemplative seclusion. His emphasis lay on direct experiential realization through samādhi and vipassanā, treating Nibbāna as a real and attainable goal rather than a distant ideal. In this way, he countered more ritualistic or worldly tendencies and reoriented monastic life toward mindfulness, investigation of body and mind, and the eradication of defilements.

Through this rigorous approach, Ajahn Mun effectively defined a recognizable style of forest practice: disciplined, simple, and deeply rooted in recollection of the Buddha, mindfulness of death, and continuous meditative effort. He trained an entire generation of forest masters, thereby transforming a personal path of wandering asceticism into a coherent lineage with clear standards. His disciples regarded him as a figure of profound spiritual authority, and their accounts of his life and practice became a template for later teachers and practitioners. In integrating intense meditative experience with respect for orthodox Theravāda, he gave the movement both spiritual vitality and doctrinal legitimacy.

Ajahn Chah inherited this forest ethos and reshaped it into a form that could be lived and understood by a broader community, while still preserving its essential rigor. Maintaining the emphasis on Vinaya, renunciation, and forest simplicity, he placed strong weight on clear, down‑to‑earth teaching that spoke directly to the concerns of both monastics and laypeople. His Dhamma talks and training style highlighted mindfulness in the flow of daily activities, not only in formal meditation sessions, and used communal life as a crucible for seeing through self, views, and preferences. In this way, discipline was not mere rule‑keeping but a skillful use of conventions in service of wisdom and letting go.

By establishing monasteries such as Wat Nong Pah Pong as stable training centers, Ajahn Chah created a communal model that balanced the solitude of forest practice with the structure of organized monastic life. Within this framework he trained both Thai and Western disciples, encouraging them to found branch monasteries that preserved the core forest principles while adapting to diverse circumstances. His openness to international students and his accessible mode of expression allowed the Thai Forest Tradition, as shaped by Ajahn Mun, to spread well beyond its original geographical and cultural setting. Through their complementary roles—Ajahn Mun as reviver and defin­er of the path, Ajahn Chah as consolidator and transmitter—the Thai Forest Tradition emerged as a living, coherent, and widely influential expression of meditative Theravāda.