 This study addresses the critical need for improving Type 1 Diabetes T1D health outcomes in high-risk youth A1C9-12; ages 10-17 yrs AIC: glycated hemoglobin where suboptimal glycemic control has severe acute and long-term complications with potentially life threatening consequences. Lack of regular contact with T1D care providers, continued T1D nonadherence, and suboptimal behavioral and mental health functioning compromises the physical health of youth with T1D and the ability of T1D teams to provide effective treatment. If the aims of this study are achieved, this study will change T1D care practices by providing high-risk youth with T1D, and their parents, medical and behavioral health support via home telehealth intervention. This has the potential to significantly change access to T1D care, decrease time spent in hyperglycemia, reduce the frequency of hospital admissions, and improve glycemic control. In addition, this studys use of Multiphase Optimization Strategy MOST, a highly efficient experimental strategy to determine effective intervention components, should be generalizable to all individuals with T1D, leading to cost-effective, home telehealth intervention programs. Innovative aspects include: 1 assessment of physical and behavioral health characteristics associated with high-risk status; 2 delivery of home telehealth that incorporates: 2a medical and behavioral health care delivered with the endocrinologist and behavioral health specialist working together with high-risk youth; 2b personalized intervention to improve T1D adherence and T1D clinical health outcomes; 2c personalized intervention to improve mental health comorbidities and T1D clinical health outcomes; and 3 an underused methodological approach for optimizing intervention components to be delivered at point of care. 