Introduction Youth with brachial plexus birth injuries (BPBI) have an increased risk of mental health issues such as depression, anxiety, and diminished self-confidence. Despite this evidence, current standards of care focus on physical interventions. Evaluation of psychological and emotional concerns is rarely prioritized in clinical settings. Therefore, mental health needs are unmet and poorly understood. Methods An interpretivist qualitative approach was used to understand the perspectives of youth with BPBI and their caregivers on the barriers and facilitators of addressing mental health concerns, to inform practice guidelines, and promote meaningful participation within this population. Results A purposeful sample of nine youth with BPBI between 10 to 20 years and eight caregivers participated in in-depth interviews. The interviews were semi-structured and an average of 60 min (35–85 min) long. Three themes emerged from these data: (i) physical disability identity and mental health; (ii) pursuit of “normal” body image; and (iii) paradox of advocacy. Findings illuminated the intersection of physical and mental health in these youth and provides actionable practice recommendations. Areas of need were identified including mental health support around the challenges of advocacy, body image, surgery, and preparation for the ‘aging out’ process for youth and their families. Conclusions The well-being of youth with BPBI is a result of the intersection between their physical and mental health. Further research on optimizing mental health resources within physical health settings is needed to better support the holistic needs of these youth and their families.