Bankhead and Winfield Scott entered the army on the same day and they remained lifelong friends.
Later he was on the staff of General Wade Hampton, and received a brevet promotion to lieutenant colonel.
He saw active service during the Second Seminole War and received a brevet promotion to colonel in 1838 to recognize his bravery.
[2] Bankhead served in the Mexican–American War, at Vera Cruz commanding the 2nd Artillery Regiment and was promoted to brevet Brigadier General for distinguished service in the reduction of Vera Cruz where Bankhead, the senior field officer, acted as chief of artillery, in command of the batteries.
Bankhead was appointed commander of the Department of the East in 1854, and made his headquarters at Fort McHenry, where he served until his death.