Some veterans face elevated risk of mental illness, alcohol, and drug use, and difficulty adjusting post-deployment, which can increase the risk of homelessness and contact with the criminal justice system (Elbogen et al., 2012). This study adds to the limited and mixed findings regarding factors associated with criminal offending among veterans. It explores, from veterans’ perspectives, what contributes to their criminal justice involvement. In-depth interviews with 28 U.S. Veterans on probation or parole explored their military service, mental health, and the events surrounding arrests. Findings indicate that substance use was a significant contributor to arrests. Alcohol and drugs were used to cope with trauma, interpersonal stress, and their transition from military service to civilian life. Some veterans indicated that substance use was evident and problematic prior to military service, while others found the military culture and conditions post-service contributed to problematic use. Veterans also entered the criminal justice system due to difficulties adjusting to civilian life and economic disadvantage.