Some criminal defendants with mental illness may not be referred to traditional mental health jail diversion programs because they have a history of non‐compliance with treatment, or complex personal circumstances such as homelessness. To successfully divert such individuals, Connecticut has developed a specialized program called the Advanced Supervision and Intervention Support Team (ASIST), which offers criminal justice supervision in conjunction with mental health treatment and support services. An evaluation of the ASIST program included a six‐month follow‐up study of 111 program clients to examine mental health functioning and other outcomes, and a comparison of administrative data for 492 ASIST clients with a propensity‐matched group to examine recidivism. Follow‐up study clients showed improvements in mental health. Administrative data showed no change in arrest rates, but a significant reduction in re‐incarceration. These findings must be viewed with caution due to the quasi‐experimental design of the study, but it appears that greater attention to criminogenic needs in addition to defendants' mental illness may help jurisdictions to divert a wider variety of defendants.