The jail‐based competency treatment (JBCT) model has become an established forensic practice across the country. From the perspective of implementation science and the three core elements of the Promoting Action on Research Implementation in Health Service (PARiHS) framework, the JBCT model is a remarkable example of how context (an unrelenting and overwhelmingly strong demand for forensic beds) has driven multiple state governments to facilitate implementation of a methodology in the absence of empirical evidence supporting its efficacy. This 7‐year study of outcomes from four JBCT program sites provides this much‐needed evidence by showing that JBCT restored 56% of 1553 male and 336 female patients over an average of 48.7 days. At the same time, the study highlights how variations in JBCT models, methods, and preadmission stabilization time present challenges to planned and effective implementation of evidence‐based practice at the statewide system level. By identifying differential responsiveness to JBCT treatment by diagnosis and other factors, the study suggests preliminary implementation ideas for what types of patients are well served by the JBCT model as part of a continuum of restoration options that includes inpatient, outpatient and diversion. Significant findings showed that JBCT patients were restored at a higher rate and in a shorter time if they were female, < 20 years old (highest restoration rate; those < 60 years old also significantly better rates), free of co‐occurring intellectual and cognitive deficits, and malingering. Of the major diagnoses, schizoaffective disorder required a significantly longer length of JBCT treatment for restoration, and lower restoration rates than schizophrenia and bipolar disorder, although this was moderated by a significant interaction with abuse of amphetamines.