William Grimes Mordecai was born on July 25, 1892, in Raleigh, North Carolina. Mordecai was a lawyer by training who served as a record clerk in the North Carolina Adjutant General's Office during World War I until he was called into active service in late July 1918. He received on honorable discharge on November 30, 1918. Mordecai spent much of his professional life a prosperous attorney in Raleigh, where died on October 13, 1985.