Social connections are essential to health and well‐being. However, when pursing social acceptance, people may sometimes engage in behavior that is detrimental to their health. Using a multi‐time‐point design, we examined whether the structure of an emerging network of students in an academic summer school program correlated with their physical health and mental well‐being. Participants who were more central in the network typically experienced greater symptoms of illness (e.g., cold/flu symptoms), engaged in riskier health behaviors (e.g., binge drinking), and had higher physiological reactivity to a stressor. At the same time, they were happier, felt more efficacious, and perceived less stress in response to a strenuous math task. These outcomes suggest that social ties in an emerging network are associated with better mental well‐being, but also with poorer physical health and health behaviors. Copyright © 2014 John Wiley & Sons, Ltd.