James Garland Sturgis was born 24 January 1854 near Albuquerque, New Mexico Territory, son of First Lieutenant (later Colonel & Brevet Major General) Samuel Davis Sturgis, Sr. and Jerusha (Wilcox) Sturgis. He was second of three children, the others being Nina Linn (born 1852) and Samuel Davis, Jr. (born 1862).
JGS entered United States Military Academy at West Point, New York 1 July 1871. Upon graduation 16 June 1875, he was appointed Second Lieutenant, Seventh U. S. Cavalry and assigned to Troop M upon reorting to the regiment. He was temporarily attached to Troop E during the campaign during which he was killed.
His father, Colonel of the regiment since 1869, is said to have heavily mourned the loss of his son for the remainder of his life. Colonel Sturgis retired from the Army in 1886 and died little more than three years later at the relatively young age of 66.