Introduction: In the USA, syringe services programmes (SSPs) provide a range of harm reduction services and have numerous benefits for communities. However, stigma, misconceptions about SSPs and changing policies/legislation remain a challenge to effective implementation. This study reviews the implementation of two digital interventions, Appalachian Influence and Shared Influence, which used social media influencers and digital volunteers to communicate positive information about harm reduction and SSPs. Methods: The intervention was designed to deliver accurate and supportive messaging in locally relevant and meaningful ways. Messaging was informed by interviews with subject matter experts and community organisations, and was integrated into prompts used by local influencers (paid individuals with more than 1,000 followers) and digital volunteers (unpaid individuals with no following requirement, who joined the project independently). Results: In the first 6 months of implementation, Appalachian Influence and Shared Influence engaged a total of 9,014 individuals, 236 of whom were paid influencers and 8,778 of whom were digital volunteers. Paid influencer posts achieved a total of 868,943 impressions, 42,432 engagements and 1,567 comments. Comments on paid influencer posts were overwhelmingly positive, with 87.4% positive and 0.8% negative. Interviews showed the importance of understanding local realities, leading with compassion and emphasising the 'human' aspects of dependency and addiction in messaging. Conclusion: This study shows the potential to implement an influencer-led social media intervention to reach people with authentic and compassionate messaging about harm reduction and SSPs. Future research should examine intervention effectiveness and how this approach can be applied to other stigmatised topics.