Updated: November 30, 2021

Don Diego de la Vega (portrayed by Guy Williams) is depicted as a former University student, newly recalled by his father from Spain to his home outside El Pueblo de Nuestra Señora Reina de los Ángeles sobre El Rio Porciuncula (later shortened as Los Angeles). Just before reaching California, Diego learns of the tyranny of Captain Monasterio, and realizes that his father, Don Alejandro, summoned him to help fight this injustice. Although he won medals for his fencing back in Spain, Diego decides that his best course of action is to conceal his ability with a sword, and to affect the demeanor of a milquetoast intellectual rather than a decisive man of action.

His alter ego, Zorro, operates primarily at night, taking the direct action that Diego cannot. This deception does not always sit well with Diego, especially as it affects his relationship with his disappointed father. In reality, Diego relies heavily on his wits, both with and without the mask on. Later in the series, Diego emerges as a respected figure in his own right, a clever thinker and loyal friend who just happens to be hopeless at swordplay. The character's name in Johnston McCulley's writing and previous adaptations was Diego Vega; the Disney version expands the name to Diego de la Vega, an innovation retained in some subsequent versions of the story. Diego's singing voice is supplied by Bill Lee of the Mellomen.