<p>The clergy role in the Church of England makes demands unlike those of any other profession, yet the established quantitative literature on clergy wellbeing has treated personality, psychological type, and emotional intelligence as relatively stable individual-level variables, measuring the outcomes of ministerial engagement without theorising the mechanism by which role and context actively constitute the minister over time. This article reports a qualitative investigation of that mechanism, drawing on semi-structured interview data from 25 Church of England archdeacons, analysed through a four-stage procedure comprising conscious attention, thematic analysis, ontological formation analysis, and emotional exegesis. The term <i>ontological</i> is used in its philosophical and theological sense – concerning the constitution of being rather than surface functioning – and the construct of the <i>ontological engine</i> is proposed to name a dynamic, recursive, and directional formation process through which sustained inhabitation of the clergy role and ministry context appears to transform the minister at the level of identity, self-understanding, and relational capacity, generatively or corrosively. Thematic analysis identifies seven substantive patterns: three role factors (role ambiguity, the clerical role as defence against authentic selfhood, and role differentiation as the ground of ministerial identity) and four contextual factors (corrosive encounter, temperament mismatch, activist time culture, and breach of the psychological contract), followed by a thematic conclusion addressing the engine’s generative pole. It is distinguished from role theory, person–environment fit theory, and professional socialisation by its emphasis on mechanism, directionality, and recursion. The findings carry implications for initial ministerial education, clergy appointments, and pastoral supervision.</p>