Spencer Carter (post-war name: Spencer Scott) was born around 1833 in Albemarle County, Virginia. His enslaver, John Coles Carter, migrated from Virginia to Missouri in 1852 and owned 126 slaves on multiple farms by the eve of the war. Carter worked as a preacher at Lick Farm in Lincoln County, Missouri. Prior to enlisting, he married his first wife Eliza, who was also owned by John Coles Carter. Together they had two children: Jennie Scott, whose birth date is not known, and an unknown child. Sometime after Carter ran away to enlist, Eliza Brown remarried. For 3 years prior to his enlistment, Carter suffered from disease of his urinary organs which resulted in a fistula, an abnormal connection between one's organs.

Carter enlisted as a private at the age of 30 on December 10, 1863, in Troy, Missouri, and mustered in on December 18 at the Benton Barracks in St. Louis. His service record describes him as 5 feet, 6 inches tall, with black hair, black eyes, and copper complexion. He served in Company A of the 65th USCT Infantry Regiment. Due to his fistula, Carter served detached duty as a carpenter, as he was unfit for combat duty. He served with the 65th USCT throughout Louisiana during his time in the war. He mustered out on December 17, 1866, in Baton Rouge, Louisiana, once his term of enlistment expired.

The night Carter mustered out, he married his second wife, Mildred Scott. Carter returned to Missouri and first lived in Paynesville for ten years. They then moved to Danville, where Mildred died on January 16, 1886. Carter then returned to Paynesville, where he lived for the rest of his life. Soon after returning to Paynesville, Carter married his third wife Amanda Scott (Mandy Scott) on December 23, 1888. Together they had one child: Lydia Scott, born on August 27, 1890 in Paynesville. Following the war, Carter worked as a Methodist minister as well as a carpenter and a shoemaker. He was able to receive a pension despite his application being invalidated at one point due to a lawyer being disbarred for questionable veracity. Carter died of influenza on February 23, 1899, in Paynesville. Following his death, Mandy Scott was able to receive a pension for herself as his widow and for their minor daughter Lydia.