Successful public health initiatives require multi-sector collaboration. AVONet was a UK collaborative developed to provide evidence-based strategies for active ageing. This study explored the success of AVONet in the achievement of its objectives as perceived by all partners. A convergent parallel mixed-methods design was employed, utilizing a quantitative survey and qualitative semi-structured interviews. Data collection was undertaken in September 2010, 18 months after establishing the collaborative and 6 months after funding had ceased. AVONet partners (n = 24) completed a 27-item survey. A sub-sample of four academics and four practitioners participated in semi-structured interviews. Quantitative and qualitative comparisons were made between academics' and practitioners' perceptions of success, potential for sustainability and satisfaction with structure and relationships. Participants perceived the AVONet collaborative positively. Significant between-group (academic v practitioner) differences in survey responses were observed for success (U = 19.5; p = 0.003) and structure (U = 125.5; p = 0.001). Strong positive correlations were observed between success and structure and balance between information transfer and exchange (r = 0.756; p < 0.001). Interviews confirmed positive perceptions and perceived importance of the collaborative and highlighted the need for further integration and tangible outcomes for practitioners. Suggestions to enhance sustainability were provided, such as smaller working groups and local council-led governance. Perceived success in building a multi-sectoral collaborative can be achieved during a 10-month period, despite differing needs of contributors. For collaboratives developed as a result of external funding aimed primarily at facilitating research, involvement of practitioners at an early stage may help set more comprehensive goals, supportive communication strategies, and increase potential for sustainability.