A member of one of Ohio's most prominent military families, he performed well at the Battle of Gettysburg, and then led a cavalry division in the army of Major General William T. Sherman during the Atlanta Campaign.

Kenner Garrard briefly attended Harvard University in Cambridge, Massachusetts, but withdrew in his sophomore year after accepting an appointment to the United States Military Academy.

After being formally exchanged on August 27, 1862, Garrard was appointed colonel of the 146th New York Infantry in the Army of the Potomac and took part in the battles of Fredericksburg, Chancellorsville, and Gettysburg, where he succeeded Brig.

In December 1863 he was nominated for promotion to brigadier general with an effective date of July 23, 1863, commemorating the end of the pursuit of Lee's Army of Northern Virginia.

Garrard took part in Sherman's Atlanta Campaign as a cavalry division commander, but failed to impress his superiors.

Garrard remained in the regular army after the war ended as commander of the District of Mobile, but resigned on November 9, 1866.

He wrote: Nolan's System for Training Cavalry Horses (1862) New International Encyclopedia[citation needed] He died in Cincinnati, Ohio, at the age of fifty-one and was interred in Spring Grove Cemetery.