While filming on location in Veracruz, Mexico, Mel Gibson learned that an elderly Mexican extra was suffering from cancer. Gibson got the man a visa by writing to the American ambassador, and then personally arranged for him to be flown to an alternative cancer therapist in Arizona.
In addition to "Get the Gringo", only one other Mel Gibson movie has been narrated by Mel Gibson as the lead character: "Payback". In Get the Gringo, Mel Gibson explains how he was once married but his wife ran off with his former business associate. This same situation actually takes place in Payback where his wife and business partner double-cross Gibson to run away together. Also, in both movies Gibson is a thief.
"Payback" (1999) is also a movie where the character, Porter, played by Gibson has only a one word name. In "Get the Gringo", Gibson appears in the credits as Driver and many, such as Harry Knowles of "Ain't it Cool News" have speculated that "Get the Gringo" may be the unauthorized sequel to "Payback".
Alejandra Cuervo, a member of the production team, was hired by the producers prior to the commencement of principal photography to do extensive research, a living history, on El Pueblito that included talking with a number of its ex-inmates for first-hand experiences.
The only subtle difference between the character of Porter in Payback, and of Driver in Get the Gringo is the Military background and associated tattoos. In Payback Porter was an ex Marine, with USMC tattoo on his arm. In Get the Gringo he is a former Army Sniper, with a Sniper tattoo.