Charles Garrison Harker (December 2, 1837 – June 27, 1864) was a brigadier general in the Union Army during the American Civil War.

Harker graduated in 1858 with the brevet rank of second lieutenant in the 2nd U.S. Infantry and was assigned to garrison duty at the United States Army post on Governor's Island in New York Harbor.

With the outbreak of the Civil War, Harker was assigned to duty in Ohio to help train newly recruited volunteer soldiers.

Harker received praise for his significant contributions during the Battle of Stones River at the end of the year while leading the 3rd Brigade, 1st Division, Left Wing of XIV Corps of the Army of the Cumberland.

After participating in the fighting around Chattanooga and the assault on Missionary Ridge, he and his men helped relieve Maj. Gen. Ambrose E. Burnside during the Siege of Knoxville.

Unlike the real Harker, who died at 26, for dramatic purposes the film portrays him as an older general who authorizes plunder and corruption among his subordinates.