The Massachusetts Patient-Centered Medical Home Initiative (MA PCMHI) was a three-year multi-payer demonstration designed to promote clinical model transformation in practices across the state and prepare the practices for PCMHI recognition. It was a partnership between MassHealth, the Massachusetts Medicaid program, and UMass Medical School. An analysis of the project at 46 participating practices finds that primary care practice transformation takes time; care transitions, including emergency room and post-discharge follow-up care, require the development of new clinical workflows; and the processes of care are more likely to improve before outcomes are affected. These lessons learned can aid provider organizations nationwide: focus on highest-risk patients, prioritize high-volume hospital systems for information-sharing; streamline documentation of the workflow in the electronic health record; and clearly identify the role and function of each care team member in the new process.