Purpose To explore the perceived and potential roles of pharmacists in the care of young people aged 10–24 years with chronic illness, through the exemplar of juvenile arthritis, from the perspectives of UK community and hospital pharmacists, health service commissioners, rheumatology health professionals, and lay advocates. Methods A sequential mixed methods study design comprises the following: focus groups with community and hospital pharmacists; telephone interviews with pharmacy and rheumatology stakeholders and commissioners; and multidisciplinary group discussions to prioritize roles generated by the first two qualitative phases. Results The high priority roles for pharmacists, identified by pharmacists and rheumatology staff, were developing generic health care skills among young people; transferring information effectively across care interfaces; building trusting relationships with young people; helping young people to find credible online health information; and the need to develop specialist expertise. Participants identified associated challenges for pharmacists in supporting young people with chronic illness. These challenges included parents collecting prescription refills alone, thus reducing opportunities to engage, and pharmacist isolation from the wider health care team. Conclusions This study has led to the identification of specific enhancements to pharmacy services for young people, which have received the endorsement of a wide range of stakeholders. These suggestions could inform the next steps in developing the contribution of community and hospital pharmacy to support young people with chronic illness in the optimal use of their medication.