Thomas was the son of Adeline Eliza Anne Crowder and Dr. Thomas F. Green, Sr., the superintendent of the Lunatic Asylum in Milledgeville, Georgia. Thomas, Jr., had many siblings, including a sister, Martha Crowder Green, who married Dr. Charles L. Bass in 1858. During the Civil War, Thomas, Jr., served in the 4th Regiment, Georgia Volunteers, Company H, and in 1864 transferred to Phillips' Legion, Georgia Cavalry. After the war, he married, practiced law in Knoxville, Georgia, and had several children before his early death.