James C. Davis was born around 1840 in Clarion County, Pennsylvania, probably to Elijah Davis and Sarah Moore. His father was a farmer who owned $8,000 of real estate in 1850. Davis moved to Missouri by the early 1860s, and he enlisted in the 5th Missouri Militia Cavalry on February 26, 1862. According to his service records, he was 6 feet, 1 inch tall, with brown hair and blue eyes. He eventually earned a promotion to sergeant. On September 7, 1864, he transferred to the 13th Missouri Cavalry at the rank of sergeant. He mustered out on January 11, 1866. He died sometime after 1866.