Objective To learn if a quality of care Medicaid child psychiatric consultation service implemented in three different steps was linked to changes in statewide child antipsychotic utilization. Data Sources/Study Setting Washington State child psychiatry consultation program primary data and Medicaid pharmacy division antipsychotic utilization secondary data from July 1, 2006, through December 31, 2013. Study Design Observational study in which consult program data were analyzed with a time series analysis of statewide antipsychotic utilization. Data Collection/Extraction Methods All consultation program database information involving antipsychotics was compared to Medicaid pharmacy division database information involving antipsychotic utilization. Principal Findings Washington State's total child Medicaid antipsychotic utilization fell from 0.51 to 0.25 percent. The monthly prevalence of use fell by a mean of 0.022 per thousand per month following the initiation of elective consults (p = .004), by 0.065 following the initiation of age/dose triggered mandatory reviews (p < .001), then by another 0.022 following the initiation of two or more concurrent antipsychotic mandatory reviews (p = .001). High‐dose antipsychotic use fell by 57.8 percent in children 6‐ to 12‐year old and fell by 52.1 percent in teens. Conclusions Statewide antipsychotic prescribing for Medicaid clients fell significantly at different rates following each implementation step of a multilevel consultation and best‐practice education service.