FitzJohn Porter was an army officer.
A graduate of West Point (class of 1845) he had a chequered military career. He rose to the rank of Major General of Volunteers under McClellan, but after the battle of Second Manassas Pope accused him of failing to obey a command to bring up his troops in support, and he was court-martialled and dismissed in 1863. He was reinstated by Act of Congress in 1886.
Cullum Memorial Edition, Register of Graduates and former cadets, United States Militery Academy, West Point, 1980.