Kappa Alpha Order was originally founded as Phi Kappa Chi on December 21, 1865, at Washington and Lee University in Lexington, Virginia. The four founding fathers included James Ward Wood, William Archibald Walsh, and brothers William Nelson Scott and Stanhope McClelland Scott. Soon after the founding, the local chapter of Phi Kappa Psi protested the name "Phi Kappa Chi," due to the similarity of the names, leading Wood to change the name of the fraternity to KA by April of 1866. The popular Kuklos Adelphon society had gone defunct during the Civil War, and it is suspected that Wood selected the letters KA to attract those who were familiar with the old society. Within one year, the fraternity's ritual (which was a version of another fraternity's ritual by the name of Epsilon Alpha that faultered after the war) would be expanded upon and given a new vision by "practical founder," Samuel Zenas Ammen. In the years that followed, the Order spread throughout the Southern United States, as well as many other states such as California and New Mexico, a distinguishing factor that separates it from the smaller, northern-based Kappa Alpha Society.

KA is one-third of the Lexington Triad, along with Alpha Tau Omega and Sigma Nu. Robert E. Lee, whose ideals of chivalry and gentlemanly conduct inspired the founders, was designated the "Spiritual Founder" of the Order by John Temple Graves at the 1923 Convention.