Background: Acute stroke outcomes depend on timely reperfusion. In 3/2017, local EMS agencies implemented a prehospital triage algorithm with hospital bypass and field activation of the neurointerventional team using the Field Assessment Stroke Triage for Emergency Destination (FAST-ED). A score ≥4 bypasses to a comprehensive stroke center (CSC) and a score ≥6 also has the interventional team field activated off-hours. Aim: We analyzed effects of this initiative on volume, acute stroke transfers, treatment times, and outcomes and determined the tool's ability to predict large vessel occlusion. Methods: Stroke cases brought to our center by EMS during 3/2016-2/2018 were analyzed, which included one year before and after FAST-ED implementation. Treatment times were compared on- vs. off-hours and to those with field activation. Results: Of 1153 patients, 761 (67%) were coded as stroke and 235 (20%) underwent reperfusion. Age, sex, race/ethnicity, stroke severity, length of stay, door-to-needle, and 90-d mRS were comparable between periods. Scale compliance was 85%. Concordance rate of ±1 between EMS and calculated score was 53%. Compared to the previous year, door-to-puncture (DTP) improved by 17 min (p < 0.01) overall, 25 min (p < 0.001) off-hours, and 33 min (p < 0.05) with field activation. A cutoff of 4 vs. 6 would have led to 140% increase in field activations but only 36% increase in procedures. Conclusions: This prehospital initiative led to faster DTP by up to 33 min. The highest impact was off-hours with field activation. Only 1/3 of activations led to endovascular treatment. FAST-ED≥6 appears to be appropriate for field activation.