Chastain was born September 21, 1848 in South Carolina, the son of Charles "Chuck" Chastain and Selena Barnese Chastain. Columbus had one known sibling, a younger brother Gadberry Chastain, born August 12, 1849 in South Carolina. The family moved from South Carolina to the Cherokee & Cobb County, Georgia area in the 1850s. Friend Chastain has been presumed by some to have died by about 1860, but appears on the 1870 Census in Kennesaw, Cobb County, Georgia with Selena. Gadberry and his family were next door.
According to his service record, Columbus enlisted in Company C, 41st Georgia Infantry on March 4, 1862 at Camp McDonald in Cobb County. His name is listed variously as Columbus P. or C. P. Chastain, Chastane, Chasteen, Chastien. He enlisted in the same company on the same day as his cousins, Lieutenants Peter R. and John D. Chastain. Seven months later, he marched with the 41st into the Battle of Perryville KY, a part of the attack of Maney's Brigade on the federal left--some of the most severe fighting of the battle.
The Roster of the Confederate Soldiers of Georgia, 1861-1865, Muster Roll of Company C, 41st Georgia Infantry – Bartow, Cherokee, Cobb, & Paulding Counties – "Acworth Invincibles", includes "Chastain, Columbus P. - Private March 4, 1862. Wounded at Perryville, Ky. October 8, 1862, captured October 9, 1862, and died there, from wound in knee, December 27, 1862."
The database at the Perryville Battlefield State Historic Site confirms his age, the fact that he was mortally wounded in action, hospital, and the date and place of death.
Columbus was treated at the Goodnight Confederate field hospital. The service record gives the name of the Confederate surgeon who treated him as John L. Alston, CSA.
Two letters from a Georgia attorney, wherein his mother claimed what was due him from the Confederate government, verify several facts:
"I, Selena Chastain, of the county of Cobb & the state of Georgia..." "...that she is the Mother of C. P. Chastain..." and that Columbus departed this life "without having Father Wife Child or Children survive him."
The service record also includes pages for a Charles Chastain who was captured at Perryville KY October 9, 1862, and was in federal military prisons through at least May 17, 1863. If this other soldier was indeed Columbus' father, he was apparently presumed dead at the time, as indicated in Selena's statement.
Daniel R. Smith, 27th Tennessee Infantry (Maney's Brigade), stated in his pension application that he had been assigned to care "for wounded comrades at Goodnight hospital near Perryville, KY where I remained till the last wounded soldier died two months later." To verify Smith's claim, Lorenzo Goodnight Hankla, who lived on the property and had helped bury the dead after the battle, affirmed that Smith had been assigned to the hospital. He had given the wounded "every care and attention till the last one died or was taken away. This was at least as late as Dec. 25th, 1862 and is the best recollection of affiant that it was some time later than Dec. 25, 1862 (This date is fixed in his mind by reason of the fact that he was on the Goodnight farm on Christmas day 1862)." Columbus Chastain died December 27, 1862.
Roster of the Confederate Soldiers of Georgia, 1861-1865 lists Pvt. James C. Cooper and Pvt. Andrew J. Willis in the same company as Columbus Chastain (C, 41st Georgia). Both were left with the wounded at Perryville as nurses. Cooper was himself wounded, remaining as a nurse at the hospital for an unspecified time. Willis was "left as nurse at Perryville, Ky. Oct. 8, 1862. Union records show he was paroled at Harrodsburg, Ky. between December 28, 1862 and January 9, 1863." This indicates that Willis was also at the hospital until Columbus died.
Chastain is buried in Goodknight Cemetery in Boyle County.