Perhaps because self-estrangement is inherently dysfunctional, empirical research has primarily sought to understand its antecedents but not its consequences. As a result, despite its ubiquity in the workplace, self-estrangement’s insidious effects are not well understood. In this paper, because coworkers frequently bear the brunt of interactions with self-estranged workers, we sought to understand how the behavior of self-estranged workers corrodes their social exchange relationships with coworkers. In particular, we focus on how increasing self-estrangement, through its dysfunctional influence on the quality of social exchange relationships with coworkers, can exact a toll on estranged workers’ job performance. To provide greater insight into their relationships, we extend social exchange theory by specifying three behavioral outcomes that underlie the quality of ongoing, reciprocal exchanges, including the level of trustworthiness, accessibility, and peer citizenship behavior. To test our model, we gathered matching survey data in a large corporation from three sources, including 346 professional employees, a knowledgeable coworker, and their supervisor. Results show that self-estrangement indirectly impacts job performance and damages relationships with coworkers by reducing the estranged workers’ level of trustworthiness, accessibility, and peer citizen behavior. We also found that each of these behavioral outcomes served as a significant intervening mechanism separately, as well as when they were combined as a set, suggesting that coworker social exchange quality should be viewed as multidimensional.