Purpose: This paper highlights important lessons for co-innovation drawn from three ex-post case study innovation projects implemented within three sub-sectors of the primary industry sector in New Zealand. Design/methodology/approach: The characteristics that fostered co-innovation in each innovation project case study were identified from semi-structured interviews conducted with key stakeholders in each project, iterative discussions to confirm the findings and secondary document analysis. Common themes from the three cases are examined in relation to innovation system structure and function analysis and agricultural innovation system (AIS) literature. This study builds on the literature attempting to overcome methodological challenges in the applied AIS research space. Findings: The findings have implications for co-innovation in practice; that there needs to be network-level capability and legitimacy, an understanding of priorities between actors, and adequate resources, to ensure proposed outcomes are likely to be attained. Practical implications: Practically, project leaders need to ensure they embed an appropriate mix of actors in the research program and they also need to create and encourage room for open and honest dialogue between these actors to develop a shared vision of the future. Theoretical implications: A conceptual model is developed to highlight and simplify lessons that can inform future projects involving co-innovation approaches to create value in the primary industries and AIS more generally. This model is unique to the applied AIS research space and provides new insights on enhancing the potential value of a co-innovation approach. Originality/value: The paper adds to current scholarly debates and provides insight to key actions stakeholders need to take to foster co-innovation processes for successful outcomes in extension.