It is widely known that personality traits collectively discussed as the Dark Triad are antagonistic and associated with poor interpersonal relationships, but few studies have examined how specific facets of antagonism are associated with psychosocial adjustment or how antagonism relates to psychosocial adjustment other than interpersonal functioning. The purpose of this study was to examine how 6 antagonism facets—manipulativeness, grandiosity, attention-seeking, hostility, callousness, and deceitfulness—relate to comprehensive psychosocial functional domains (i.e., well-being, interpersonal relationships, basic daily functioning) using information about both antagonism and functioning from 3 sources—self, informant, and interviewer. Data were from 318 primary participants and informants. We present 3 main findings: (1) When psychosocial functioning and antagonism traits were both rated by informants, all psychosocial disability domains were consistently positively associated with antagonism traits. (2) We next created a single psychosocial-disability factor score via principal factors analysis of all raters’ psychosocial-functioning scores. When all 3 raters’ reports of domain-level antagonism were used as independent variables in a simultaneous regression analysis to predict this overall functioning score, informant-reported antagonism most strongly predicted psychosocial functioning, followed by interviewer-rated antagonism. (3) We then created 6 facet scores by summing the 3 raters’ scores on each. When we used these scores to predict psychosocial functioning, hostility was the main trait significantly predicting psychosocial functioning. The study provides further insight into associations of psychosocial disability with antagonism facets from different raters’ perspectives. The findings thus further our understanding of psychosocial outcomes associated with antagonism, the core of the dark traits.