With generous funding from the Bill & Melinda Gates Foundation, in February 2014, the Washington P-3 Executive Leadership Certificate Program (P-3 ELCP) enrolled its first cohort. The P-3 ELCP was offered in three subsequent years, and as of the end of 2017, 162 administrators from ECE and K-12 completed the program. This report presents an overview of the unique design features of the P-3 ELCP and an evaluative summary of what was learned during the four years the Program was offered. (author abstract)