The U.S. health care system is in the midst of major transformation, requiring a shift from the traditional patient and provider roles to a more collaborative partnership. Patient engagement has been identified as both a goal and strategy to lower health care costs and improve health outcomes. However, there is a lack of consensus and clarity in identifying patient engagement as a concept, and more importantly, how the process of patient engagement occurs between patient and providers. For this reason, there is an urgent need to understand the underlying and crucial components of effective patient engagement to inform both patients and providers as to the expectations and responsibilities of their new relationship and roles as active collaborators in care. A mixed methods exploratory design was used to gain a comprehensive understanding of patient engagement. Guided by the Interactive Care Model, a directed content analysis was used to analyze three hundred nursing narratives, written by advanced practice mental health nurses describing in detail how they engaged low-income depressed mothers in a mental health and parenting intervention. Quantitative analysis was then employed to examine how nursing engagement strategies were employed in the three phases of the nurse-mother interpersonal relationship and in response to various levels of mothers’ engagement. The Interactive Care Model was validated by the nursing narrative data and captured the process of patient engagement with a traditionally underserved population. The key process components and partnership roles of the ICM are fluid, dynamic, with different components operating at different intensities and frequencies depending upon the phase of the mother-nurse relationship and level of mother’s engagement. Engagement skills and strategies were significantly limited when mothers were minimally engaged- underscoring the importance of the work and time spent in the orientation phase and gaining some degree of patient engagement. Demographic differences between the nurses and the mothers, built in power inequalities and dynamics, and reflective practice, were not addressed in the ICM and should be added to enrich the model and to enhance patient engagement.