The core of developmental trauma (DT) can be considered the chronic frustration of the innate drive for sharing subjective experiences, namely, intersubjectivity. According to some of the clinical literature, DT is ubiquitous. It may therefore concern not only the patient but also the therapist. However, while there is a huge amount of theoretical reflection and empirical research about patients’ DT, what seems to be underrepresented is the study of therapists’ DT and its impact on the clinical exchange. In this article, through a “parallel” analysis of a clinical case and its supervision process, we show (a) that the therapeutic relationship may implicitly take the form of a sort of short circuit between the patient's and the therapist's DT, which prevents the therapist from intersubjectively attuning with the patient and (b) that a process of supervision specifically focused on the therapist's DT can effectively promote this attunement and a good clinical outcome.