As reported earlier, nurse practitioners (NPs) and physician assistants (PAs) play a critical role in the delivery of primary care in California, providing the majority of primary care services in over 20% of the state’s community clinics. This follow-up, qualitative research explores how and why leaders in a sample of these clinics rely on NPs and PAs, in addition to physicians, as primary care clinicians. As described, these models help meet high patient volume in a cost-effective manner. Some of the opportunities and challenges of an integrated clinician model – staffing arrangements, oversight mechanisms, practice culture and ideas for making these models work even better – are investigated and described.