Rooted in both the self-concept based theory of transformational leadership and the conservation of resources (COR) theory, transformational leadership is hypothesized to elicit follower-felt support for excellence and, through it, follower psychological capital (PsyCap), resulting in high follower job performance as well as work engagement. We examined this three-path mediation model with change scores from a two-wave study of 149 Indonesian healthcare workers. When applying structural equation modeling to the change scores, the integrated model was supported. Further cross-lagged analysis showed that transformational leadership had a lagged effect on follower PsyCap and that follower PsyCap had, in turn, a lagged effect on follower job performance. Hence, PsyCap is proposed as a parsimonious element in the self-concept-based theory of transformational leadership. Moreover, the results suggest that the transformational style can be added as a so-called "key" resource to COR's notion of "gain spirals."