Griffith was then-Colonel Jefferson Davis’s first lieutenant and adjutant in the Mexican War, where Davis mentioned him for gallantry in several reports. The 47-year-old Jackson banker was a Pennsylvania native, an honor graduate of Ohio University, and a teacher when he came to Vicksburg to teach at a private school.
After the Mexican war, he went into business and politics, with part ownership of a Jackson nursery that sold fruit trees and serving two terms as state treasurer. He was married with five children, including one who would serve in the Confederate army. He owned 36 slaves, according to the federal 1860 slave schedules census.
Griffith had raised his own infantry company for the new war and was colonel of the Twelfth Mississippi Regiment when his old friend President Davis promoted him to brigadier general and gave him command of the victors of Leesburg/Ball’s Bluff—the Thirteenth, Seventeenth, and Eighteenth Mississippi regiments (plus the newly-arrived Twenty-First regiment). Under him, they would soon become the Third Mississippi Brigade of Magruder’s Division.