Victor McLaglen actually served with the Irish Fusiliers in Mesopotamia (modern-day Iraq) during World War I at the same time this story takes place. He eventually rose to be Provost Marshal--equivalent of Police Chief--of Baghdad.
According to Boris Karloff biographer Peter Underwood the temperature on the Yuma locations could be as hot as 150 degrees and actors were limited to working two hours a day.
The film was panned by critics due to Karloff's erratic and over-the-top performance.
Director John Ford's older brother Francis Ford appears in an uncredited role. Francis appeared in many of his brother's pictures in small or uncredited roles.
Composer Max Steiner re-used the main title music he wrote for this film for the main title music for Casablanca (1942), albeit with a slightly different tempo and instrumentation.