Background We evaluated a community‐engaged stroke preparedness intervention that aimed to increase early hospital arrival and emergency medical services (EMS) utilization among patients with stroke in the South Side of Chicago, Illinois. Methods and Results We compared change in early hospital arrival (<3 hours from symptom onset) and EMS utilization before and after our intervention among patients with confirmed ischemic stroke at an intervention hospital on the South Side of Chicago with concurrent data from 6 hospitals in nonintervention communities on the North Side of Chicago and 17 hospitals in St Louis, Missouri. We assessed EMS utilization for suspected stroke secondarily, using geospatial information systems analysis of Chicago ambulance transports before and after our intervention. Among 21 497 patients with confirmed ischemic stroke across all sites, early arrival rates at the intervention hospital increased by 0.5% per month (95% CI, −0.2% to 1.2%) after intervention compared with the preintervention period but were not different from North Side Chicago hospitals (difference of −0.3% per month [95% CI, −0.12% to 0.06%]) or St Louis hospitals (difference of 0.7% per month [95% CI, −0.1% to 1.4%]). EMS utilization at the intervention hospital decreased by 0.8% per month (95% CI, −1.7% to 0.2%) but was not different from North Side Chicago hospitals (difference of 0.004% per month [95% CI, −1.1% to 1.1%]) or St Louis hospitals (difference of −0.7% per month [95% CI, −1.7% to 0.3%]). EMS utilization for suspected stroke increased in the areas surrounding the intervention hospital (odds ratio [OR], 1.4; 95% CI, 1.2–1.6) and in the South Side (OR, 1.2; 95% CI, 1.1–1.3), but not in the North Side (OR, 1.0; 95% CI, 0.9–1.1). Conclusions Following a community stroke preparedness intervention, early hospital arrival and EMS utilization for confirmed ischemic stroke did not increase. However, ambulance transports for suspected stroke increased in the intervention community compared with other regions. Registration URL: https://www.clini​caltr​ials.gov ; Unique identifier: NCT02301299.