This practice note details the synchronous implementation and developmental evaluation of a novel model of care that integrates an evidence-based treatment of children with disruptive behaviour within a community-based children's mental health centre in Canada. The overall objective of the project was to evaluate the impact and viability of the integrated program. A multidisciplinary team used a "knowledge to action" framework to guide implementation activities and a developmental evaluation approach to support learning and innovation, as well as measure program success. Key insights and lessons learned with regards to building staff capacity and appreciation for evaluation, balancing clinical and evaluation practices, and sustaining evaluation procedures are discussed. Suggestions for future similar efforts within a children's mental health context are provided.