Research which indicates that adverse experiences influence hypothalamic‐pituitary‐adrenal (HPA) axis functioning illustrates the social environment ‘getting under the skin’. The present study extended this literature by examining whether positive social forces within the caregiving environment can also impact cortisol functioning. We conducted a prospective investigation of over 300 youth, half of whom were White and half were Black. Attachment, bonding and parental rewards for positive behaviors were observed or reported by the youth as an 8th grader. Twelve repeated measures of salivary cortisol were examined six years later when youth were young adults (mean age 20). Race differences were explored. Stronger attachment, bonding and teen‐reported positive parenting were predictive of high waking cortisol and steeper diurnal slopes six years later. This effect was nonlinear and additive, such that youth whose social contexts were characterized by the strongest attachment, bonding and rewarding parental relationships had the highest waking cortisol. When effects were moderated by race, findings were such that links of positive parenting with HPA functioning were more consistent for White than Black youth. Findings suggest that positive aspects of the caregiving environment can also ‘get under the skin’ and these effects are additive across a range of caregiving indices. These findings dovetail with an emerging literature on the powerful role of social support for shaping the body's stress response system and are interpreted as consistent with the Adaptive Calibration Model which suggests that cortisol regulation can have adaptive significance. A video abstract of this article can be viewed at: https://youtu.be/8evHXpt_TXM. In a prospective investigation of over 300 youth, half of whom were White and half were Black, we found that stronger attachment, bonding and teen‐reported positive parenting were predictive of high waking cortisol and steeper diurnal slopes six years later when youth were emerging adults. When effects were moderated by race, links of positive parenting with HPA functioning were more consistent for White than Black youth. Positive aspects of the caregiving environment may also “get under the skin” and these effects are additive across a range of caregiving indices.