Objective The aim of this study was to examine the experience of volunteer psychiatrists who provided mental health interventions to adolescents and teachers of Danwon High School from April 16, 2014, to November 30, 2014. Methods Data for this study were collected from 72 volunteer psychiatrists about their intervention experiences for 212 adolescents and 32 teachers during the eight months following the disaster. Developmental survey themes were identified, and coding was used to analyze the data. In addition, qualitative data analysis was performed using ATLAS.ti (version 8.2, 2018, ATLAS.ti GmbH). Results A volunteer prepared with appropriate mental health interventions may facilitate the emergency response to a disaster. Intervention services included psychological first aid, psychoeducation, screening, anxiety reduction techniques, and group therapy. Conclusion In the acute aftermath of the Sewol Ferry disaster of April 16, 2014, volunteer psychiatrists were able to provide mental health interventions in a disaster response setting. The outcomes from this study have important policy and mental health system implications for volunteer psychiatrists. The results of this study constitute the basis of a better understanding of the essential mechanisms of crisis interventions after a disaster.