Although research has examined and supported the role of environmental adversity in career decision-making, little is known about the prediction power of childhood environmental adversity for career decision-making. To provide guidance for early career interventions, particularly in disadvantaged populations, the current study drew on life history theory and used a sample of U.S. college students ( n = 310) and a sample of U.S. noncollege individuals during emerging adulthood ( n = 308) to examine a mediation model involving childhood unpredictability, childhood poverty, career decision ambiguity aversion, and career decision-making difficulty. The results support the mediation of ambiguity aversion in the positive predictions of childhood unpredictability for all four factors of career decision-making difficulty. However, the results do not support the indirect predictions of childhood poverty for all four factors of career decision-making difficulty through ambiguity aversion but support the direct prediction of childhood poverty for lack of readiness. Therefore, the current study illuminates the importance of a predictable family environment during childhood for career decision-making during emerging adulthood and provides implications for the validity of life history theory in career decision-making, the development of ambiguity aversion, and early career interventions. Implications and future directions of research regarding childhood poverty are also discussed.