Despite the emotional challenges of parental adjustment to a child's type 1 diabetes diagnosis and the unique complexities of early childhood, there are few programs designed to meet the needs of parents of young children at new onset. This study evaluated First STEPS (Study of Type 1 in Early childhood and Parenting Support), a stepped-care behavioral intervention designed to support parents' psychosocial functioning and promote children's glycemic outcomes. Using a two-site randomized clinical trial design, parents (n = 157) of children aged 1-6 years completed baseline data within 2 months of diabetes diagnosis and were randomly assigned to intervention (n = 115) or usual care (n = 42) for 9 months. Intervention steps included: 1) peer parent coaching, with step-ups to 2) structured behavioral counseling and 3) professional consultations with a diabetes educator and psychologist, based on parent mood and child HbA1c. Participants completed follow-ups at 9 and 15 months postrandomization. Primary outcomes were parent depressive symptoms and child HbA1c. Depressive symptoms improved in both groups, and intervention parents had significantly lower depressive symptoms at the 9- and 15-month follow-ups compared with usual care. HbA1c decreased in both groups, but there were no between-group differences at 9 or 15 months. First STEPS improved parents' mood following young children's type 1 diabetes diagnosis. Results indicate likely benefits of parent coach support, supplemented by intervention intensifications, including behavioral intervention and diabetes education. This model has high potential for patient engagement. The absence of a medical intervention component may explain null findings for HbA1c; incorporating targeted behavioral support for intensive diabetes treatment may maximize intervention impact.