The centrality of emotion in cognition and social intelligence as well as its impact on health has intensified investigation into the causes and consequences of individual variation in emotion regulation. Central processing of experience directly informs regulation of endocrine axes, essentially forming a neuro-endocrine continuum integrating information intake, processing, and physiological and behavioral response. Two major elements of life history—resource allocation and niche partitioning—are served by linking cognitive-affective with physiologic and behavioral processes. Scarce cognitive resources (attention, memory, and time) are allocated under guidance from affective co-processing. Affective-cognitive processing, in turn, regulates physiologic activity through neuro-endocrine outflow and thereby orchestrates energetic resource allocation and trade-offs, both acutely and through time. Reciprocally, peripheral activity (e.g., immunologic, metabolic, or energetic markers) influences affective-cognitive processing. By guiding attention, memory, and behavior, affective-cognitive processing also informs individual stances toward, patterns of activity in, and relationships with the world. As such, it mediates processes of niche partitioning that adaptively exploit social and material resources. Developmental behavioral neurobiology has identified multiple factors that influence the ontogeny of emotion regulation to form affective and behavioral styles. Evidence is reviewed documenting roles for genetic, epigenetic, and experiential factors in the development of emotion regulation, social cognition, and behavior with important implications for understanding mechanisms that underlie life history construction and the sources of differential health. Overall, this dynamic arena for research promises to link the biological bases of life history theory with the psychobehavioral phenomena that figure so centrally in quotidian experience and adaptation, particularly, for humans. Am. J. Hum. Biol. 2009. © 2009 Wiley-Liss, Inc.