The serial is unusual in featuring a real historical personage, Mexican President Benito Juárez, as a minor character.

[3] A man named Francisco is put in charge of a fighting legion to combat the Yaqui tribe and protect the gold; he is attacked by men working for Don Del Oro.

Francisco asks Diego, as Zorro, to take over the fighting legion and defeat Don Del Oro.

[2] In the early 1950s, Zorro's Fighting Legion was one of fourteen Republic serials edited into a television series.

The date given for the movie is 1824, which in and of itself establishes that it takes place well after Zorro's California adventures: Zorro opposed a corrupt Spanish Colonial government in his canon tales, and California ceased being a Spanish Colony in 1821.