This session will present accomplishments and lessons learned from the AHRQ-PCORI Institutional Mentored Career Development Program which funded 11 institutions to support the training of embedded researchers to conduct patient-centered outcomes research and comparative clinical effectiveness research (CER) within learning health systems (LHS). The AHRQ-PCORI Learning Health System Embedded Scientist Training and Research (LHS E-STaR) Centers program is the next phase of this work and integrates lessons learned from the K12 award. The session will explore the implementation of AHRQ-developed core competencies for training patient-centered CER professionals to become LHS scientists and the approaches taken to develop LHS embedded research infrastructure, training of scientists, strengthen partnerships among health system and community stakeholders, and impacts on care delivery.