Halbert was born in Pickens County, Alabama and was raised in Lowndes County, Mississippi. In 1857, Halbert earned an M.A. from Tennessee's Union University. He served with the Texas State troops in 1860. Most of his Texas military action was against Indians. When the American Civil War began, Halbert enrolled with the 6th Texas Cavalry Regiment, Confederate Army. He was wounded at New Hope, Georgia in 1864.