Evidence from existential–humanistic psychology suggests that addiction is a response to boredom, loneliness, meaninglessness, and other existential struggles. This research is a case study of an existential, meaning-centered therapy practiced at an addiction treatment facility. Meaning therapy assumes that addiction is a response to a life that lacks personal meaning. The solution, therefore, is to help the client live a fulfilling life. The research question asked if, and in what ways, meaning therapy influenced how participants made sense of their addiction and recovery. The study used a mixed-methods design. Sources of qualitative data were pretreatment and posttreatment interviews, psychiatric reports, researcher field notes, and participants’ life stories. Quantitative data were pretreatment and posttreatment measures of items relevant to meaning and symptom reduction. Eleven participants volunteered for the study. Themes that emerged during a grounded theory thematic analysis revealed that therapy positively influenced nine (81.8%) participants in developing self-definition, interpersonal relatedness, and intrinsic motivation. Quantitative analysis revealed significant increases in measures of meaning and decreases in symptoms and daily problems for seven participants (63.6%). About 6 to 9 months posttreatment, eight participants (72.7%) who pursed self-definition, relatedness, and intrinsic motivation reported abstinence since discharge, fewer symptoms and problems in daily life, and the pursuit of personal goals. This study provides therapists with a better understanding of meaning therapy and suggests implications for addiction treatment.