The ways we resonate with patients is shaped and informed by our experience, history, and subjectivity. This article reviews theory, infant research, and neuroscience to consider the developmental origins of the analyst's resonant responses to the analysand—one aspect of countertransference. In the context of a contemporary psychoanalytic sensibility, this article refers to this experience as relational attunement or “analytic knowings”—an emergent, co-created component of the analytic dyad. The article illustrates how the analyst's pre-reflective relational “knowings” emerge within the analytic encounter influencing our experience of the patient. The focus is on presenting one integrative paradigm for understanding the origins of the analyst's resonant responses (feelings, images, sensations, and associations) as informing the analyst's sense of the patient, as well as contextualizing and shaping the analytic interaction and process.