Background. Well-being is important for people with severe mental illness, such as psychosis. So far, no clear concept of well-being exists for this client group. A recent systematic review and narrative synthesis developed a static framework of well-being components. The present study aims to validate the static framework and to illuminate the processes by which well-being is experienced by people with psychosis. Methods. Semi-structured interviews were conducted with 23 service users with psychosis exploring their experience of well-being. Thematic analysis was used to analyse the data employing techniques taken from grounded theory to enhance the rigour of the analysis. Respondent validation was undertaken with 13 of the 23 participants. Results. Three superordinate categories of well-being were identified: current sense of self; transition to enhanced sense of self and enhanced sense of self. In the dynamic process of improving well-being the current sense of self undergoes a transition to an enhanced sense of self. The four factors influencing the transition are consistent with the static framework of well-being, hence validating the static framework. In addition, we identified three determinants of current sense of self and seven indicators of enhanced sense of self, which represent the achievement of improved well-being. Conclusions. This study provides an empirically defensible framework for understanding well-being in terms of determinants, influences and indicators. The influences are targets for interventions to improve well-being, and the indicators are outcome domains to assess the effectiveness of services in supporting well-being.