Jacob S. Delo was born around 1840 in Clarion County, Pennsylvania. By the early 1860s, he was working as a coal miner. He enlisted in the Union army on August 1, 1861, and he mustered in as a private in Company F of the 63rd Pennsylvania Infantry. According to his service records, he was 5 feet, 8 ¾ inches tall, with light hair and blue eyes. The regiment took part in the Peninsula campaign and the Seven Days Battles. He was wounded in the Battle of Glendale on June 30, 1862, and he died in Wilkinsburg, Pennsylvania, on November 28, 1862.