This paper aims to contribute to our understanding of the unique role of enactment in the dynamics of motivation and participation in prefigurative social movements, with the intention of providing a deeper understanding of the mechanisms, inherent to prefiguration, driving change through collective action. We achieve this through examining what motivates people to participate as activists in a social movement trying to enact changes within the National Health Service (NHS) in the United Kingdom. To do so, we explore the narratives of 23 activists working to develop the NHS Change Day movement. The narratives describe how NHS frontline staff engage in daily grassroots change activities while having to navigate top-down, planned, organisational change interventions. We analyse our findings in light of recent developments in the understanding of group identity processes in the mobilisation of collective action, and highlight the role of enactment in these dynamics. The findings indicate that it is not the overall top-down managerial strategies, but rather the daily participation and enactment of self-initiated small-scale change actions that gives meaning and direction to the activists’ participation in the social movement – a meaning which is constructed through the encapsulation of a sense of personal agency and collective efficacy, contributing to a sense of the affirmation of vocational and organisational identity. We contend that the relationship between the experience of the daily enactment of self-initiated activities within a supportive group setting and the motivation to participate in collective action is mutually constructed, and as such, inextricable.