In addition to the surgeon Major Kendall and Miss Hunter, Marlowe also must contend with Col. Phil Secord, a politically ambitious officer commanding the other cavalry regiment.

In April 1863, Colonel Benjamin Grierson led 1,700 Illinois and Iowa soldiers from La Grange, Tennessee, to Baton Rouge, Louisiana, through several hundred miles of enemy territory, destroying Confederate railroad and supply lines between Newton's Station and Vicksburg, Mississippi.

[4] Grierson's destruction of Confederate-controlled rail links and supplies played an important role in disrupting Confederate General John C. Pemberton's strategies and troop deployments.

"[6] Dr. Erastus Dean Yule, the real-life surgeon counterpart of Major Hank Kendall, actually did volunteer to stay behind and get captured by the Confederates with the casualties who were too wounded to continue.

[11] Lukey's dialog was originally written in "Negro" dialect that Althea Gibson, the former Wimbledon and U.S. National tennis champion who was cast in the role, found offensive.

[13] During filming of the climactic battle scene, veteran stuntman Fred Kennedy suffered a broken neck while performing a horse fall and died.

[15] The film opened at number one in the United States[16] but was ultimately a commercial failure, due largely to Wayne's and Holden's high salaries and the complex participation of multiple production companies.

[15] Literary critic Manny Farber writing in The New Leader offers this assessment: The Horse Soldiers is the disaster of the month, an eventful canter in which director Ford, without any plot to speak of, falls back on boyish Irish playfulness (played by a rigor-mortified John Wayne, an almost non-existent Bill Holden, and a new gnashing beauty named Connie Towers) to fill a several-million-dollar investment.

The ‘comedy’ which includes Wayne’s troubles with a drunken top sergeant, a soldiering doctor, and a captive Southern belle, is interspersed with Ford’s stolidly evolved, beefy, Bonheur-ish ‘pictures.’ It all takes place on a plodding journey, which sends 1,700 hundred Union cavalrymen into the Confederacy in search of what turns out to be a screenplay.”[17]