Family-focused interventions can improve outcomes for families where a parent has a mental illness. One such intervention, Let's Talk about Children (Let's Talk), is a series of parent-practitioner conversations in adult mental health with demonstrated improved outcomes for child, parent, and family well-being. This study used a questionnaire to understand the application of Let's Talk by n = 73 trained practitioners from eight adult mental health services who were previously involved in a randomized controlled study in Victoria, Australia. Data were analysed to establish the application of Let's Talk, and statistical analyses were undertaken to identify what influenced practitioners' delivery of Let's Talk. The study details how practitioners used Let's Talk and indicates that most used it as designed, with the majority offering it to parents and approximately 40% delivering it. The findings indicate there is a decline over time in both the number of practitioners using Let's Talk and the number of deliveries over time. Practitioners' use of Let's Talk was influenced by their gender, profession, access to support, time since training, and caseload. The article discusses the implications of these results for sustaining Let's Talk in adult mental health services. While this study gives a baseline of practitioners' application of Let's Talk, further exploration of the experience of practitioners and parents as well as other system factors will be helpful to understand barriers and enablers to continued practice.