Intervention programs to prevent childhood obesity are more likely to be successful when mothers are involved and engaged. Yet programs that involve mothers do not often employ process evaluation to identify aspects of the intervention that participants enjoyed or viewed as useful. The aims of this study were to describe how participants of the Melbourne InFANT Program-an early childhood obesity prevention intervention-engaged in the program and perceived its usefulness. Process evaluation data were collected at multiple time points during and after the intervention, using mixed methods drawing upon both quantitative and qualitative data. Results from short surveys (n = 271) and interview transcripts (n = 26) revealed that the Melbourne InFANT Program was perceived as useful and relevant by most (82-93%) participants. The formats through which the knowledge and skills were delivered were considered concise and effective, and aspects considered particularly useful included group sessions and advice on practical strategies to minimize stress around mealtimes. Findings from this study are important to inform future practice and the development of interventions which are well received by participants.