John M. Brewer appears to have enlisted as a private in 1862 at Elbert County, Georgia which was his home.
Later, in 1863, he transferred to 24th Battalion Georgia Cavalry Co. B and was elected 3nd Lt.
On February 13, 1864 was transferred to Co. C, 7th Regiment, Georgia Cavalry as Jr. 2nd Lt.
Surrendered April 1865 in Virginia.