Purpose: The study was conducted to explore the experiences of job retention among working people with mental illness. Methods: The participants were members with mental illness at the S Community Mental Health Center in Gyeonggi Province and who had been working for more than six months. The data were collected through in-depth interviews with 11 participants between June 27 and August 20, 2018. The data were analyzed through Corbin and Strauss’s grounded theory method. Results: The core category was struggling to take root in the community as a productive member. The core phenomenon was the desire to be a productive person, and the causal condition was the willingness to change for a purposeful life. The action and interaction strategies included maintaining regular living patterns, maintaining medication, developing one’s tips for self-management, and self-approval. The intervening conditions were difficulties in forming social relationships, presence of symptoms, social resources, and acceptance of one’s mental illness. The consequences were restoration of family relationships, healthy pleasure through work, social inclusion, development of self-worth, and transition to an independent person. Conclusion: Working people with mental illness are struggling to take root in the community as a productive member. This study suggests that a holistic understanding of the job retention experience among people with mental illness is required. The findings will provide the basis for developing interventions that can improve job retention among working people with mental illness.