This research examined how core self-evaluation (CSE) develops from social support in the career context and how it influences individuals’ life satisfaction. Study 1 used a field survey to collect data from 768 university students for testing the mediating role of CSE in the relationship between career social support (CSS) and life satisfaction. Study 2 employed two experiments with two groups of participants (n = 103 for Experiment 1 and n = 102 for Experiment 2) to further verify the Study 1 findings obtained from cross-sectional data. The results from these two studies showed that CSE mediated the CSS-life satisfaction relationship in such a way that CSS served as a cause of CSE, which in turn affected individuals’ life satisfaction. Among the first to use both field study and experiments to confirm the antecedent (i.e., CSS) and outcome (i.e., life satisfaction) of CSE, this research offers useful insights regarding CSE as a causal mechanism underlying the effect of CSS on life satisfaction and carries important theoretical and practical implications.