Youth debt has increasingly evolved into a structural social risk intertwined with employment instability and housing burdens. This study examines the effects of debt restructuring programs for financially vulnerable youth from a social investment perspective. Using comprehensive credit bureau data from Korea Credit Bureau (KoDATA) for 2020-2025, combined with survey data and expert interviews, the study adopts a mixed-methods approach. The results show that youth have a higher prevalence of multiple loans and rely heavily on entry-level financial products such as student loans, unsecured credit, and housing-related loans, while mid-term delinquency (one to three years) is particularly concentrated among them. Among financially vulnerable youth, participants in debt restructuring programs demonstrate better outcomes than non-participants, including improvements in employment status, working hours, and prospects for income recovery. Positive changes are also observed in life satisfaction, social participation, and reduced debt-related stress. These findings suggest that debt restructuring programs can support the economic recovery and social reintegration of financially vulnerable youth beyond simple debt relief. The study highlights the need to shift youth debt policy toward a preventive and recovery-oriented social investment framework with early monitoring and integrated post-restructuring support systems.