Emotional, behavioral, and mental health challenges make it difficult for many children and adolescents to engage and succeed at school. Research indicates that at least 20% of all children and adolescents have been diagnosed with one more mental health disorders. Behavioral problems, anxiety, and depression are the most diagnosed mental health issues, and they often co-occur. Moreover, these conditions are being diagnosed at increasingly younger ages. In the past several years there has been a rise in the number of adolescents and young adults with serious mental health issues such as major depression and suicidal ideation, and the COVID-19 pandemic has exacerbated mental health problems for children and adolescents. Schools offer promise for providing intensive clinical support to the most at-risk students, and schools are necessary environment to explore the implementation of multi-modal youth mental health services. This paper provides an analysis of an intensive, in-school mental health services model developed and implemented by Effective School Solutions (ESS), a New Jersey based provider of high acuity school based mental health services for K-12 students. We analyze this multi-modal model for its effectiveness in improving educational outcomes for over 3,000 students identified as requiring intensive clinical mental health support across the 2021-22 school year. This analysis reveals that those students receiving High- versus Low-fidelity programming (i.e., multiple sessions per week for at least half of the school year versus for less than half of the school year) had better educational outcomes. Students receiving High-fidelity programming had greater improvements in grade point average (GPA) and greater reductions in absences across the school year. A higher number of in-school clinical sessions per week significantly predicted a greater increase in GPA and a greater reduction in total disciplinary incidents (including out of school suspensions) across the school year. This report provides initial promising evidence that in-school intensive mental health clinical services yield positive effects on students' educational outcomes. Though future research is needed to validate and extend these findings, schools may consider implementing such services onsite to meet students where they are and to optimize students' mental, behavioral, and educational well-being. [This white paper report was published by the Yale Child Study Center."]