Abstaining from substance use is a goal of many people with alcohol use disorder (AUD). Understanding patient perspectives of a period of abstinence may assist persons with AUD in achieving this goal. We accessed the electronic health records of adults with AUD entering an emergency department in Baltimore, Maryland, who received a brief peer support intervention for substance use. Data contained open-ended text entered by staff after a patient indicated ever having a sustained period of substance abstinence. Using qualitative template analysis methodology, we identified codes and themes from these open-ended responses from N = 153 adults with AUD. The sample was primarily male (n = 109, 71.2%) and White (n = 98, 64.1%) with an average age of 43.8 years (SD = 11.2). Themes identified included the abstinence length, abstinence reason, relapse, triggers, time of relapse, and treatment. The most common code for abstinence length was “between 1 and 5 years” (n = 55, 35.9%). Other abstinence length codes included “less than 1 year” and “more than 5 years.” Relapse triggers included “family (non-death),” “death of a loved one,” “social,” “economic,” and “treatment-related” reasons. Findings from this study could be used to inform strategies for peer support interventions to assist patients with substance abstinence.