Background: The implementation strategies used to facilitate the delivery of youth mental health interventions are rarely reported. Specifying and reporting implementation strategies for impactful innovations that have demonstrated good clinical outcomes has the potential to support replication in other contexts and accelerate adoption of effective youth mental health interventions. Methods: Key project personnel conducted a retrospective review of implementation strategies used in a national programme of enhanced primary care youth mental health services. These strategies were classified and reported using the pragmatic implementation-reporting tool. We used univariate statistics to describe the implementation strategy types, temporality, dosage, and actors. We conducted linear regression techniques to predict time investment. Results: We identified 30 implementation strategies used across the course of one year. Twenty percent of strategies identified were in the domains of evaluative and iterative strategies and developing stakeholder engagement. This was followed by training and educating stakeholders, providing interactive assistance and supporting clinicians. In terms of dosage, interactive assistance accounted for over half of all time invested. Regression analysis showed that interactive assistance was the only category to predict increased person hours. Conclusions: By specifying and reporting the implementation strategies used in a youth mental health primary care programme, the pragmatic implementation-reporting tool can help demonstrate resourcing and skills required to reach programme sustainment.