This study examines the serial dual mediating effects of marital conflict and self-esteem on the relationship between parenting stress and life satisfaction in parents of school-aged children with chronic conditions. This study aims to present foundational data for developing nursing interventions for parents caring for children with chronic illnesses. Of the 2150 parents who participated in the 13th Panel Study on Korean Children (PSKC), 271 raising a child with a chronic illness were enrolled in the study. The serial dual mediating effect was analyzed using PROCESS macro Model 6. The serial dual mediating effects of parenting stress, marital conflict, and self-esteem on parents’ life satisfaction were analyzed. Marital conflict and self-esteem had significant serial multiple mediating effects on the relationship between stress and life satisfaction in fathers (B = −0.11, bootstrap 95% CI = −0.16–−0.06) and mothers (B = −0.06, bootstrap 95% CI = −0.09–−0.03). Our results suggest that marital conflict increases with increasing parenting stress and that increased marital conflict sequentially reduces self-esteem, ultimately diminishing life satisfaction in parents raising a child with a chronic condition. Thus, relevant nursing interventions and social support are essential to boost the life satisfaction of parents raising children with chronic conditions.