Studies show interdisciplinary treatment is highly effective for addressing chronic pain syndromes, including headache disorders. Increasingly, advanced practice pharmacists work collaboratively with physicians to apply their unique skills to enhance patient outcomes. This qualitative study aimed to elucidate the potential in the Veterans Health Administration (VHA) for increased roles of clinical pharmacist practitioners (CPPs)-advanced practice pharmacists with a scope of practice-in collaborative, interdisciplinary headache care teams. Our research question was: How do CPPs integrate with interdisciplinary headache care teams in Headache Centers of Excellence (HCoE) and non-HCoE VHA facilities, and how can their roles be configured to optimize headache specialty care services? This cross-sectional qualitative study used purposive sampling to recruit CPPs providing headache care within HCoEs and in non-HCoE VHA facilities for virtual, recorded, individual interviews. Multi-stage qualitative data analysis entailed: team discussions; immersion/crystallization for close reading of transcripts to identify emerging patterns of HCoE/non-HCoE comparison of CPPs' experiences; team data sorting using spreadsheets; and further immersion into sorted data for final identification of comparisons and interpretation of the data. A total of 15 CPPs involved in headache care were interviewed, with about half working in HCoEs and half in non-HCoE VHA facilities across the United States. CPPs' roles within and outside HCoEs have considerable overlap as both groups co-manage patients with headache with physicians. CPPs have independent and collaborative responsibilities as they extend headache specialists' services by providing direct patient care and referring to additional providers for headache treatment. When their roles differ within and outside HCoEs it is largely due to level of integration on interdisciplinary headache or pain teams. CPPs in HCoEs collaborate with headache neurologists and interdisciplinary teams; some outside HCoEs do as well, while others work with primary care. CPPs' weekly time dedicated specifically to headache tends to be greater in HCoEs. Nevertheless, most interviewees in both groups stated patient need exceeds CPP availability at their facilities for conducting detailed chart reviews, initial visits to understand the context of patients' headache, and scheduled follow-ups over time to monitor and adjust treatment. CPPs also consult with and educate physicians on headache pharmacy, particularly regarding appropriate use of non-formulary medications. Findings from this study suggest that CPPs' roles in headache care are valuable to clinical colleagues and their patients and should be leveraged and expanded within HCoEs and non-HCoE VHA facilities. When substantively integrated into interdisciplinary headache care teams, CPPs offer unique knowledge, headache management and patient behavior change skills, extend headache specialists' services, and provide both patient and physician education. These combined responsibilities contribute to enhancing patient outcomes and facilitating ongoing access to high quality, evidence-based headache care.