Background Despite growing attention to the general therapist effects in a wide range of clinical settings, little is known about the individual, cross‐situational, and therapy–nonspecific variables that impact on the differential effectiveness of clinicians. The current study is a systematic review of the evidence relating to the influence of therapist's subjective characteristics on outcomes of psychodynamic psychotherapies. Method A multistage and systematic search of articles published between 1987 and 2017 identified 30 relevant studies, which were organized into 6 areas according to the specific therapist's variable considered. Results Therapists' interpersonal functioning and skills showed the strongest evidence of a direct effect on treatment outcomes. Furthermore, there were preliminary evidence that therapists' attachment styles, their interpersonal history with caregivers, and their self‐concept might affect outcomes through interaction effects with other constructs, such as technical interventions, patient's pathology, and therapeutic alliance. The high variability between studies on therapists' overall reflective or introspective abilities and personality characteristics suggested the need for more systematic research in these areas, whereas therapists' values and attitudes showed small effects on therapeutic outcome. Conclusions The present review clarifies how a deep examination of the contribution of therapists' subjective characteristics can help elucidate the complex association between relational and technical factors related to the outcome of psychodynamic treatments.