This study investigates the relationship between core self-evaluations, job characteristics, and job satisfaction. Core self-evaluations, which include self-esteem, generalized self-efficacy, locus of control, and low neuroticism, are hypothesized to mediate the relationship between personality and job satisfaction. Two studies were conducted to test this model. Study 1 found that core self-evaluations measured in childhood and early adulthood were linked to job satisfaction measured in middle adulthood, with job complexity mediating part of the relationship. Study 2 used longitudinal data to examine the robustness of these relationships over time, confirming that core self-evaluations measured in childhood were associated with job complexity and job satisfaction in early adulthood. The findings suggest that core self-evaluations play a significant role in shaping job satisfaction through their influence on job characteristics and complexity.This study investigates the relationship between core self-evaluations, job characteristics, and job satisfaction. Core self-evaluations, which include self-esteem, generalized self-efficacy, locus of control, and low neuroticism, are hypothesized to mediate the relationship between personality and job satisfaction. Two studies were conducted to test this model. Study 1 found that core self-evaluations measured in childhood and early adulthood were linked to job satisfaction measured in middle adulthood, with job complexity mediating part of the relationship. Study 2 used longitudinal data to examine the robustness of these relationships over time, confirming that core self-evaluations measured in childhood were associated with job complexity and job satisfaction in early adulthood. The findings suggest that core self-evaluations play a significant role in shaping job satisfaction through their influence on job characteristics and complexity.