Background Patient navigation, a patient-centered intervention to promote comprehensive health care, is an emerging innovation in obstetrics to optimize postpartum care. We aimed to evaluate the implementation of a novel postpartum patient navigation program at an urban academic medical center. Methods This mixed-methods study analyzed the implementation of a postpartum patient navigation program within an ongoing randomized control trial. This study analyzed three navigators’ logs of interactions with 50 patients, care team members, and community organizations throughout patients’ first year postpartum. We categorized and quantified interactions by topic addressed, care team member interacted with, and communication mode used. We also conducted semi-structured interviews with each navigator every three months (5 interviews per navigator), emphasizing navigation experiences, relationships with patients and care teams, integration in the care team, and healthcare system gaps. Interview data were analyzed using the constant comparative method to identify themes using the constructs of the Consolidated Framework for Implementation Research (CFIR). Results Analysis of navigator logs revealed a high patient need level, especially in the first 3 months postpartum. CFIR-guided analysis of intervention characteristics revealed positive perceptions of navigation’s utility due to its adaptability. Navigation’s complexity, however, posed an early obstacle to implementation that diminished over time. Outer setting analysis indicated navigators addressed patient needs through interactions with multiple systems. Despite clinicians’ initial unfamiliarity with navigation, inner setting analysis suggested ongoing communication and electronic medical record use facilitated integration into the care team. Regarding individual and process characteristics, findings emphasized how navigator self-efficacy and confidence increased with experience (individual) and was facilitated by comprehensive training and reflection (process). Overall, barriers to implementation included unfamiliarity, varied patient engagement, and innovation complexity. Facilitators included high patient need, communication with outside organizations, medical record usage, navigator characteristics (self-efficacy, communication skills, and personal growth), a comprehensive training period, consistent reflection, high relative advantage, and high adaptability to patient need. Conclusion Patient navigation is a promising innovation to improve postpartum care coordination and support care team efforts. The successful implementation of navigation in this study indicates that, if shown to improve patient outcomes, obstetric navigation could be a component of patient-centered postpartum care.