James Riley was born on August 4, 1835, in Northampton County, Pennsylvania. By the early 1860s, he was living in Philadelphia, Pennsylvania, and working as a jeweler. He enlisted in the Union army on October 12, 1861, and mustered in as a private in the Anderson Troop Pennsylvania Cavalry on November 30. According to his service records, he was 5 feet, 10¼  inches tall, with black hair and black eyes. He fell ill around August 1862 and spent the next several months in a hospital in Philadelphia. He mustered out on March 26, 1863. He reenlisted again soon afterward and spent the next four years in the 37th U.S. Infantry and the 21^st U.S. Infantry, eventually receiving a promotion to 2^nd lieutenant. He mustered out in 1867 and returned to Philadelphia, where he resumed his work as a jeweler. He never married. He died in Philadelphia on April 9, 1902.