Health care leaders and policymakers are turning to the patient-centered medical home (PCMH) model to contain costs, improve the quality of care, and create a more positive primary care work environment. We describe how Group Health, an integrated delivery system, developed and implemented a PCMH intervention that included standardized structural and practice level changes. This intervention was spread to a diverse set of 26 primary care practices in 14 months using Lean Management principles. Group Health's experience provides valuable insights that can be used to improve the design and implementation of future PCMH models.