His paternal ancestors were the Harrison family of Virginia, whose immigrant ancestor, Benjamin Harrison, arrived in Jamestown, Virginia, circa 1630 from England. == Marriage and early career == In 1862, President Abraham Lincoln issued a call for more recruits for the Union Army; Harrison wanted to enlist, but worried about how to support his young family. Morton offered him the command, but Harrison declined, as he had no military experience. He was initially commissioned as a captain and company commander on July 22, 1862. Morton commissioned Harrison as a colonel on August 7, 1862, and the newly formed 70th Indiana was mustered into federal service on August 12, 1862.