Purpose: This study aimed to explore the weight loss experience of highly obese young people who underwent bariatric surgery. Methods: Data were collected, from October 2021 to April 2022, through individual in-depth interviews with eight highly obese young adults who underwent bariatric surgery and analyzed using Colaizzi’s phenomenological method. Results: The following four theme clusters were extracted. First, ‘The unbearable sorrow of obese people’ explains the process of choosing bariatric surgery after fluctuations and frustration despite countless repeated weight loss attempts. Second, ‘The impact aftermath of bariatric surgery’ revealed participants struggling in the face of unexpected changes due to bariatric surgery. Third, ‘Efforts to rebuild a healthy myself’ demonstrated the struggle to regain health by using the surrounding support system to overcome the difficulties of this surgical procedure. Lastly, ‘Facing life by getting rid of the yoke of obesity’ displayed the experiences of the participants who felt ambivalent about their changed appearance, but coping positively with the new life. Conclusion This study provides an in-depth understanding of the weight loss experiences of highly obese adolescents who underwent bariatric surgery and presents a new perspective on clinical practice. The results of this study are expected to be useful in developing and applying systematic and customized nursing interventions before and after bariatric surgery.