<Table> <Tr> <Th colspan="2"> George B. McClellan </Th> </Tr> <Tr> <Td colspan="2"> 1861 photograph by Mathew Brady </Td> </Tr> <Tr> <Td colspan="2"> </Td> </Tr> <Tr> <Th colspan="2"> 24th Governor of New Jersey </Th> </Tr> <Tr> <Td colspan="2"> In office January 15 , 1878 -- January 18 , 1881 </Td> </Tr> <Tr> <Th> Preceded by </Th> <Td> Joseph D. Bedle </Td> </Tr> <Tr> <Th> Succeeded by </Th> <Td> George C. Ludlow </Td> </Tr> <Tr> <Th colspan="2"> 4th Commanding General of the United States Army </Th> </Tr> <Tr> <Td colspan="2"> In office November 1 , 1861 -- March 11 , 1862 </Td> </Tr> <Tr> <Th> Preceded by </Th> <Td> Winfield Scott </Td> </Tr> <Tr> <Th> Succeeded by </Th> <Td> Henry Halleck </Td> </Tr> <Tr> <Td colspan="2"> </Td> </Tr> <Tr> <Th colspan="2"> Personal details </Th> </Tr> <Tr> <Th> </Th> <Td> George Brinton McClellan ( 1826 - 12 - 03 ) December 3 , 1826 Philadelphia , Pennsylvania </Td> </Tr> <Tr> <Th> </Th> <Td> October 29 , 1885 ( 1885 - 10 - 29 ) ( aged 58 ) Orange , New Jersey </Td> </Tr> <Tr> <Th> Political party </Th> <Td> Democratic </Td> </Tr> <Tr> <Th> Spouse ( s ) </Th> <Td> Mary Ellen Marcy ( `` Nelly '' ) McClellan </Td> </Tr> <Tr> <Th> Parents </Th> <Td> <Ul> <Li> George McClellan </Li> <Li> Mary ( Brinton ) McClellan </Li> </Ul> </Td> </Tr> <Tr> <Th> Alma mater </Th> <Td> United States Military Academy , West Point , New York </Td> </Tr> <Tr> <Th> Profession </Th> <Td> Soldier ( General ) Politician </Td> </Tr> <Tr> <Th> Signature </Th> <Td> </Td> </Tr> <Tr> <Th colspan="2"> Military service </Th> </Tr> <Tr> <Th> Nickname ( s ) </Th> <Td> Little Mac The Young Napoleon </Td> </Tr> <Tr> <Th> Allegiance </Th> <Td> United States Union </Td> </Tr> <Tr> <Th> Service / branch </Th> <Td> United States Army Union Army </Td> </Tr> <Tr> <Th> Years of service </Th> <Td> 1846 -- 1857 1861 -- 1864 </Td> </Tr> <Tr> <Th> Rank </Th> <Td> Major General </Td> </Tr> <Tr> <Th> Commands </Th> <Td> Department of the Ohio Army of the Potomac </Td> </Tr> <Tr> <Th> Battles / wars </Th> <Td> <P> Mexican -- American War ( 1846 - 1848 ) American Civil War ( 1861 - 1865 ) </P> <Ul> <Li> Battle of Rich Mountain </Li> <Li> Peninsula Campaign <Ul> <Li> Seven Days Battles </Li> </Ul> </Li> <Li> Maryland Campaign <Ul> <Li> Battle of South Mountain </Li> <Li> Battle of Antietam </Li> </Ul> </Li> </Ul> </Td> </Tr> </Table>
who was the successful commanding general of the northern forces in the civil war
George B. McClellan