Despite antiviral agents that can cure the disease, many individuals with Hepatitis C Virus (HCV) remain untreated. Primary care clinicians can play an important role in HCV treatment but often feel they do not have the requisite skills. We implemented a population-based improvement intervention over 10 months to support treatment of HCV in a primary care setting. The intervention included a decision-support tool, education for clinicians, enhanced interprofessional team supports, mentorship, and proactive patient outreach. We used process and outcome measures to understand the impact on the proportion of patients who initiated treatment and achieved Sustained Virologic Response (SVR). We used physician focus groups and pharmacist interviews to understand the context and mechanisms influencing the impact of the intervention. Between December 2018 and June 2020, the percentage of HCV RNA positive patients who started treatment rose from 66.0% (354/536) to 75.5% (401/531) with 92.5% (371/401) of those starting treatment achieving SVR. Qualitative findings highlighted that the intervention helped raise awareness and confidence among physicians for treating HCV in primary care. A collaborative team environment, education, mentorship, and a decision-support tool integrated into the electronic record were all enablers of success although patient psychosocial complexity remained a barrier to engagement in treatment. A multifaceted primary care improvement initiative increased clinician confidence and was associated with an increase in the proportion of HCV RNA positive patients who initiated curative treatment.