Intellectually disabled youth (ID) have a high level of psychiatric comorbidity, behavioral dysregulation, and crisis-related service use. Still, systematic early risk identification models are not applied in the regular course. This paper has explored the usefulness of an early intervention model based on the Historical Clinical Risk Management (HCRM) approach to reduce psychosocial and behavioral risk factors in ID youth. The study was a prospective cohort study conducted across 10 multidisciplinary service centers and included 240 youths (mean age = 13.2 ± 2.5 years; 61% men). Historical, clinical, and risk management areas were systematically assessed using baseline assessments. The 12-month follow-up was conducted. The frequency of behavioral crisis, psychiatric hospitalizations, and school disciplinary exclusions was the primary outcome. By the baseline, 49% of participants had a psychiatric comorbidity rate of at least one, and 34% had a prior crisis-related emergency visit. After the HCRM-directed intervention plan, the general frequency of crises dropped by 37.2%, emergency service use dropped by 33%, and the average number of school exclusion days decreased to 9.3 days per year. Youth in the high-risk baseline risk group had a 39% reduction in crises, showing the largest absolute decrease of -0.94 crises per year. Multivariate regression analysis showed that the variance of crisis recurrence explained by integrated historical and clinical risk scores was 43% (R2 = 0.43). These results indicate the effectiveness of an HCRM-based systematic early intervention to mitigate the acute negative outcomes of youth with ID. Routine risk grouping and proactive management planning have the potential to improve prevention, lessen expenditures on expensive services, and increase developmental and psychosocial results.