Patients can become educator-influencers in promoting the public's understanding of health and illness; however, the underlying motivations driving their engagement in this role remain unclear. Drawing from the Self-Determination Theory, this study explores the motivations of patients-turned-influencers in sharing eating disorders (ED) experiences and information on Chinese social media. Through semi-structured interviews with 33 patient influencers, this study examines the motivations associated with three psychological needs: autonomy, competence, and relatedness. In terms of autonomy, influencers shared their ED experiences as self-therapy, expression, and documentation of personal growth. Regarding competence, influencers felt that their medical training or personal experiences made them more knowledgeable about ED, and their communication skills and high self-esteem gave them more confidence and courage to share their ED experiences. Finally, in terms of relatedness, altruism, community building, and peer influence are the driving forces behind their sharing behaviors. With the rise of ED cases in China, misunderstandings about the condition remain prevalent. As the first study of ED social media influencers in a Chinese context, this research highlights the unique cultural and social factors influencing the motivations behind sharing ED-related experiences on social media. The theoretical and practical implications of the study are also discussed.