The purpose of this study was to examine the experience of an older adult diagnosed with mild dementia during reminiscence-based art therapy for the alleviation of depression and what the experience meant for the participant. The study participant was an 82-year-old woman diagnosed with mild dementia in October 2020 who participated in 11 art therapy sessions, 60 minutes each, twice a week from May 4, 2021, to June 8, 2021. The art therapy program was developed based on Erikson’s psychosocial developmental stage model and reminiscence therapy practices. The participant’s art works, transcripts of each session, and clinical journals were collected as data and analyzed using Creswell’s five-step qualitative research methodology. Based on the collected data, the participant’s art therapy experience was classified into four themes and 14 subthemes. The broad themes were “recognizing the deep sorrow and pain in life,” “cleansing the mind through a positive reflection on life,” “accepting life and reevaluating it positively,” and “assigning value to the future.” The results demonstrated that reminiscence-based art therapy helped the participant positively evaluate the meaning of her life by enabling her to recognize her value, alleviating her depression, and encouraging her to accept her life. Based on the findings, the implications and limitations of the study were then discussed.