This study analyzes the effect of arrest and community supervision on mental health and mental health care using a U.S.-based nationally representative data from National Survey of Drug Use and Health (NSDUH) and Behavioral Model for Vulnerable Populations. It conducts a bivariate analysis to estimate population prevalence rates and generalized structural equation modeling (GSEM) to test the conceptual model. Individuals who were recently arrested or under community supervision (probation/parole) are more likely to use treatment (medication, inpatient, and outpatient care) for mental health problems compared with those with no CJ contact. However, there still remains a large unmet need. Overall, people with mental illness may be accessing mental health treatment through their involvement with the CJ system more broadly. There is the need for multiple societal institutions to work in tandem and communicate with vulnerable individuals who experience CJ contact to further assess appropriate assistance and mental health treatment.