This study aimed to investigate the associations between Japanese emerging adults’ identity configuration patterns across educational and interpersonal domains and various indices of adaptive (i.e., social trust and prosocial behaviors) and maladaptive functioning (i.e., internalizing, externalizing, and hikikomori symptoms). A total of 2,313 Japanese emerging adults completed the questionnaires. Based on the identity statuses assignments in the educational and interpersonal domains, we assigned participants to seven identity configurations. Individuals assigned to achievement/foreclosure in both domains scored the highest on adaptive functioning and the lowest on maladaptive functioning. Conversely, individuals assigned to diffusion in both domains scored the lowest on adaptive functioning and the highest on maladaptive functioning. This study contributes to identity research literature by including a socioculturally relevant symptoms, hikikomori, with a large sample size of Japanese emerging adults.