Problematic smartphone use (PSU) and its negative consequences among adolescents are so commonly observed that they have become a matter of public concern. Utilizing life history (LH) theory, this study aims to examine how childhood risks (i.e., childhood harshness and unpredictability) would be associated with adolescent PSU via cognitive and emotional processes of LH strategy and psychological distress. A sample of 459 Chinese high school students aged from 14 to 18 (M = 16.90) participated in this study and voluntarily completed an anonymous survey. The results showed that childhood unpredictability and psychological distress were positively correlated with PSU, whereas childhood harshness and the two processes of LH strategy were negatively correlated with PSU. Path analysis further supported a partial mediation model, in which childhood unpredictability increased PSU, via serial mediators of the emotional process of LH strategy and psychological distress. The findings support the efficacy of LH theory in elucidating the development of behavioral addiction. However, the direct and negative association of childhood harshness with PSU was unexpected. It implicates the complexity of childhood environment on adolescent behavioral addictions and warrants further investigation.