INTRODUCTION: Addiction support and recovery is a multi-faceted support context in which practitioners work with clients who present with increased mortality risks. Drug-related deaths are understood to be a risk factor for complicated grief-reactions but, to date, research has neglected to explore the intricacies of drug-related client loss for practitioners who work with clients experiencing addiction. Due to wider expectations of professional endurance and the demanding nature of health care, grief-related reactions associated with the loss of a client may go unprocessed and, therefore, result in long-term health implications. METHOD: Fifteen health care professionals took part in individual semi-structured interviews, which were analyzed using reflexive thematic analysis. Participants represented various disciplines in addiction support and recovery, including homelessness, inclusion health, addiction, and emergency medicine. RESULTS: Three core themes emerged encapsulating the experience of drug-related bereavement for HCPs who support people experiencing addiction, as follows: (i) Grief Beneath the Surface, (ii) The Cost of Caring, and (iii) Finding Closure. The findings identified acute grief-related reactions in HCPs such as self-blame and shame, alongside fears of litigation and questions of clinical competency. Participants' accounts of drug-related client loss emphasized a deep professional connection with those that they work with, with grief-responses akin to the loss of peers, family members, and other close connections. The bereavement experience was complicated by unique compounding variables associated with drug-related deaths, but also by incongruity between their emotional responses to death and their professional responsibilities. CONCLUSIONS: This article highlights the complex nature of drug-related client loss, and despite their social positioning as experts in their field, HCPs' reactions to client deaths were predominantly human responses to loss. The article identified a need for targeted postvention protocols that address complicated grief while also allowing staff to resume occupational functioning in a measured manner.