What makes you popular at school? And what are the labor market returns to popularity? We investigate these questions using an objective measure of popularity derived from sociometric theory: the number of friendship nominations received from schoolmates, interpreted as a measure of early accumulation of personal social capital. We develop an econometric model of friendship formation and labor market outcomes allowing for partial observation of networks, and provide new evidence on the impact of early family environment on popularity. We estimate that moving from the 20th to 80th percentile of the high-school popularity distribution yields a 10% wage premium nearly 40 years later.