Objective: to conduct public and professional involvement work to establish stakeholder views on the feasibility, acceptability, key purposes, and design of a national linked longitudinal research database for fetal alcohol spectrum disorder (FASD) in the UK. Methods: Following stakeholder-mapping, we identified contributors through collaborator networks and online searches. We consulted with stakeholders using online workshops (one for adults with FASD [and their supporters] N=5; one for caregivers of people with FASD N=7), 1:1/small-team video calls/email communication twith clinicians, policymakers, data-governance experts, third-sector representatives, and researchers [N=35]), and one hybrid clinical workshop (N=17). Discussions covered data availability, benefits, challenges, and design preferences for a national pseudonymised linked database for FASD. We derived key themes from the notes and recordings collected across all involvement activities. Results: Our tailored, multi-method approach generated high levels of stakeholder engagement. Stakeholders expressed strong support for a pseudonymised national linked database for FASD. Key anticipated benefits were the potential for: increased awareness and understanding of FASD, leading to better support; new insights into clinical profiles, leading to greater diagnostic efficiency; facilitating international collaboration; and increased knowledge of the long-term impacts of FASD on health, social care, education, economic and criminal justice outcomes. Policymakers noted clear alignment with contemporary FASD and digital transformation priorities. Given the rich data infrastructure established in the UK, stakeholders expressed that a national linked FASD database could be world-leading. Common stakeholder concerns were around privacy and data-sharing and the importance of retaining space for clinical judgement alongside insights gained from quantitative analyses. Conclusions: Multi-method and multidisciplinary public and professional involvement activities demonstrated the feasibility and acceptability of establishing a national linked database for FASD in the UK. Perceived benefits and challenges varied by stakeholder group, demonstrating that flexible, diverse, embedded stakeholder collaboration will be essential as we establish this database.