General George B. McClellan with staff & dignitaries (including): Gen. George W. Morell, Lt. Col. A.V. Colburn, Gen. McClellan, Lt. Col. N.B. Sweitzer, Prince de Joinville (son of King Louis Philippe of France), and the Count de Paris. Autumn 1861. George Brinton McClellan (1826 - 1885) was an American soldier, civil engineer, railroad executive, and politician. A graduate of West Point, McClellan served with distinction during the Mexican War (1846-1848), and later left the Army to work in railroads until the outbreak of the Civil War (1861-1865).