The impact of the Family Check-Up (FCU) on family-school engagement was tested in a randomized, controlled trial. Participants were primary caregivers of 321 children. Approximately 87% of families randomly assigned to the intervention agreed to participate and received the intervention. Caregivers in the FCU condition outperformed caregivers in the school-as-usual condition on family-school engagement at home. In addition to outcomes, implementation of the FCU during kindergarten was examined, including family participation in the FCU, dosage, consumer satisfaction, and content of the follow-up sessions when delivered by FCU therapists. Children's baseline behavior and caregiver perception of the FCU significantly predicted participation in the FCU. Implications for family-centered interventions are discussed. [This paper was published in "School Psychology" v34 p433-443 2019 (EJ1221794).]