Although a growing number of caregiver-mediated intervention models for families with children with autism are being examined in efficacy trials, few have been transferred to community implementation. Furthermore, little testing has explored implementation strategies to support caregivers' strategy use with their children. In partnership with a publicly funded intervention agency in Canada, this pilot project explored intervention implementation strategies and follow-up supports. Dyads were randomized at entry to coaching or observe then add coaching and at intervention exit to individual or group follow-up booster. The caregiver-mediated Joint Attention, Symbolic Play, Engagement and Regulation intervention was provided by agency staff to a diverse community sample of families with young children awaiting or diagnosed with autism spectrum disorder. Independent agency staff delivered assessments and recorded a caregiver-child interaction. Blinded raters scored children's initiations of joint attention, play actions, joint engagement, and caregivers' strategy implementation. Practitioners implemented the intervention and coaching strategies well (M = 83%). Overall, caregivers made significant gains in strategy use and children showed significant growth in joint engagement, play diversity, and joint attention across conditions through public caregiver-mediated intervention services. Caregivers' strategy use supported gains in children's joint engagement.