Background: The rapid evolution of social media in recent years has increased public exposure to suicide. While research has highlighted concerns about the role of social media in facilitating harmful discourse and imitative suicidal behaviour, there is a wide gap in our understanding of the impact of social media exposure in the aftermath of a suicide, and no research to our knowledge from preventive public and mental health perspectives. This qualitative study explored the experiences of public and mental health professionals in relation to social media exposure following a suicide. The study aimed to (1) Better understand social media risks from a public health perspective; (2) Provide insights for public health policy and strategy to enhance suicide prevention efforts and inform guidance for responding. Methods: In-depth interviews were conducted with 10 purposively sampled public and mental health professionals based on their roles in crisis response, suicide prevention, and digital monitoring. Data were collected through semi-structured interviews, focusing on their experiences of responding to suicide-related risks on social media, including the spread of information across platforms, public engagement with content, impact, and intervention challenges. Data were analysed using thematic analysis to identify emerging themes. Results: Four key themes emerged: (1) The communicative ecology of social media (where the public act as content purveyors, rapidly disseminating varied and often unregulated narratives); (2) Harmful effects (including the copycat effect and toxic discourse); (3) Positive effects (where protective discourse and moderation offer harm reduction opportunities); and (4) Challenges in intervention (including content moderation difficulties and algorithmic biases that amplify harmful narratives). Conclusion: Findings highlight the need for improved content moderation, public health-led digital monitoring, and education on safe social media use. Strengthening real-time suicide surveillance, improving collaboration with social media platforms, and promoting public awareness of digital literacy are critical to mitigating risks and ensuring social media supports suicide prevention efforts. As digital communication continues to evolve, proactive public health strategies will be essential in safeguarding vulnerable individuals. © The Author(s) 2025.