Vulnerable narcissism (VN), a central construct in Kohutian self-psychology, lags behind grandiose narcissism in the empirical research literature, yet a growing body of evidence suggests important implications for VN in relation to mental health and psychosocial functioning. Recent empirical research in the field of positive psychology has found negative associations between VN and the relational virtues of forgiveness and humility, while other studies have supported Kohut's theorized connection between VN and depression. The current study tested a proposed theoretical model of the relations between VN and (a) interpersonal forgiveness, (b) humility, and (c) depression with differentiation of self (DoS) as a mediator of the effects in a sample of graduate students in the helping professions (N ϭ 162) at a Protestant-affiliated university in the United States. VN was operationalized based on Self Psychology and utilizing measures of (a) idealization needs, (b) goal instability, and (c) hiding the self. The model in this study also draws on Kohutian and Bowenian understandings of DoS as an indicator of selfcohesion and capacities for self-regulation of emotions and interpersonal stress. Results based on Structural Equations Modeling supported the proposed theoretical model for 3 of the 4 measures of VN with DoS mediating the relationships between the predictor variables of approach idealization, goal instability, and hiding the self and the dependent variables of depression, forgiveness, and humility. The findings suggest the potential benefits of integrating research in psychoanalysis, family systems, and positive psychology. Implications are considered for future research, training of helping professionals, and clinical practice.