Joseph Hooker (1814-1879), American army officer, whose skillful leadership and personal bravery won for him the nickname Fighting Joe. He was born in Hadley, Massachusetts, and educated at the U.S. Military Academy. During the Mexican War he was brevetted lieutenant colonel at Monterrey. With the outbreak of the American Civil War he was appointed brigadier general of volunteers, and in 1862 he became brigadier general in the Union army.

In January 1863, Hooker was assigned by Abraham Lincoln to the command of the Army of the Potomac. He rehabilitated and organized this army, but his command on the battlefield failed to show the qualities that had distinguished him as a corps and division commander. The defeat of the Union troops at Chancellorsville in May 1863 was in large measure the result of Hooker's vacillation and inability to cope with the surprise actions of the Confederate leadership. In deference to Lincoln's lack of confidence in him and the pressure of public opinion in the North, Hooker resigned his command of the Army of the Potomac the following July and was given command of the XI and XII Corps. He fought with distinction at Lookout Mountain, in the Battle of Chattanooga (November 1863), and was brevetted major general. In 1868 he retired from the army with the full rank of major general.