Grounded in the psychology of working theory, the link between economic constraints and decent work is well established. However, previous studies did not incorporate a developmental framework when examining this relationship. Drawing on a life history perspective, this study explored how childhood socioeconomic status (SES) is associated with well-being through decent work. We adopted a dual-contextual approach, examining the interaction between childhood SES and current job insecurity as a predictor of decent work and well-being. Using data collected from 417 workers in South Korea, we tested a moderated mediation model. The results revealed significant indirect relationships between childhood SES and job and life satisfaction through decent work, particularly among individuals with higher job insecurity. Notably, these findings remained significant even after controlling for participants’ current SES. Overall, our findings suggest that in contexts where job insecurity is prevalent, an individual’s childhood SES is distinctly associated with decent work and well-being, independent of their current SES.