Acquired brain injury (ABI) confronts patients with sudden and possibly permanent functional impairments which disrupt or block the attainment of important life goals and reduce subjective well-being (SWB). This longitudinal study aimed at investigating changes in the importance and the attainability of communion and agency life goals and their impact on SWB. Self-report measures of life goals, functional status and SWB were assessed in 42 patients during acute rehabilitation two months following ABI (baseline) and reassessed 19 months following discharge (follow up). Results indicate a significant longitudinal decrease of the general attainability of life goals and of the present success in achieving communal and agentic life goals. Life goal importance remained stable. After controlling for baseline SWB and follow up functional status the attainability of communal life goals significantly predicted SWB at follow up whereas agentic life goals failed to predict SWB. The present findings show long-term deterioration of life goal attainability. They highlight that more emphasis should be given to realistic attainability attributions during rehabilitation processes. Moreover, the results stress the need for outpatient treatment to promote disengagement from unobtainable life goals and to offer means for the engagement in alternative life goals in order to maintain or regain SWB.