The story follows Jerry Welbach as he travels through Mexico to find a valuable antique gun, The Mexican, and smuggle it into the United States. Five years earlier, Welbach had caused a traffic accident in which he hit the car of local mobster Arnold Margolese, who was jailed for five years after the police searched his car following the crash, finding someone tied up in his trunk. In compensation for the jail time, Welbach has been sent on various errands by Margolese's prickly second-in-command, Bernie Nayman. Retrieving the gun will be his final errand. Welbach has a girlfriend, Samantha, with whom he argues constantly and who leaves Jerry prior to the trip over his lack of commitment to their relationship.
Jerry arrives in Mexico and makes his way to pick up Beck, the Margolese employee now in possession of the gun. There, a drunken Beck tells Jerry about the gun's history as a suicide weapon used as part of a jilted love-triangle between a woman, a nobleman, and the son of the gunsmith who forged the weapon, as well as its curse to misfire. Jerry helps Beck to his car, only for the man to be killed by celebratory gunfire from a nearby festival.
Panicked but determined, Jerry buries the body and then calls Bernie to report on the situation, only for his vehicle to be stolen while he makes the call, the gun still inside. Jerry briefly has an uncooperative donkey as transportation to follow the thief, then buys an old, damaged truck.
Meanwhile, Samantha gets kidnapped by a hit man named Leroy, who tells her that Jerry hired him to make sure she is safe from anybody that wants her dead. It is then revealed that Leroy is gay, which doesn't bother Samantha. They pick up a postal worker named Frank, who then has a relationship with Leroy.
Another hitman follows them to Las Vegas and kills Frank to make it look like a suicide. Leroy kills him in an act of vengeance, and flees with Samantha. Jerry finds out that Ted, his friend and colleague, wanted to kill him and take the pistol to Margolese, but hesitated and ends up getting handcuffed to a pawnshop owner, after he received the gun from a policeman when Jerry was being interrogated for the bloodstain on the front passenger seat of his car. Jerry then finds out he accidentally grabbed Ted's Passport and tries to retrieve his own, but Ted has already fled. Jerry decides to pick up Samantha and Leroy at the airport, where Leroy recognizes him, but Jerry doesn't recognize Leroy. Without a passport, Jerry is stuck in Mexico until further notice by the American Consulate.
After their car has a blowout, Jerry kills Leroy and finds out that he is one of Nayman's men named Winston Baldry, and that the real Leroy was the man Winston killed. Samantha begins to realize that Leroy was not who he appeared to be when they first met. Jerry realizes that Nayman's plan was to make it look like Jerry double crossed Margolese. Shocked by this, Samantha decides to go home, but also decides to stay with Jerry to see the situation to the end. Jerry gets assaulted and taken to Margolese who was released from prison a few days earlier. He tells Jerry that he didn't double cross him as it was Bernie who wanted to sell the pistol to the highest bidder.
A gunsmith, who is the great-grandson of the gunsmith from the story, wanted to bring the pistol back to where it belongs. He thanks Jerry for risking his life for the pistol he was going to give to his greedy boss. Samantha gets kidnapped by Bernie in order to get the pistol from Margolese. After opening the trunk to his car, she pulls the gun on Bernie, blaming him for ruining her life, where it ends in a Mexican standoff. Samantha gets the upper hand and kills Bernie with the pistol he desperately needed. Jerry and Samantha rekindle their romance and get married in Mexico, while Margolese finally gets his prize, as well as the gunsmith. The film ends with Jerry and Samantha arguing over the story of The Mexican on their way to Vegas.Brad Pitt as Jerry Welbach
Julia Roberts as Samantha Barzel
James Gandolfini as Winston Baldry
J.K. Simmons as Ted Slocum
Bob Balaban as Bernie Nayman
Sherman Augustus as Well-Dressed Black Man/Leroy
Michael Cerveris as Frank
David Krumholtz as Beck
Castulo Guerra as Joe
Gene Hackman as Arnold Margolese
The script was originally intended to be filmed as an independent production without major motion picture stars, but Roberts and Pitt, who had for some time been looking for a project they could do together, decided to make it, following Roberts' introduction and encouragement of the project to Pitt. Roberts also suggested the casting of James Gandolfini, in what is regarded as one of his greatest roles.
The Mexican made use of Real de Catorce, San Luis Potosí, Mexico, as a film location, as well as various areas in Las Vegas, Nevada and Los Angeles, California. Aeropuerto internacional Adolfo Lopez Mateos Toluca, Estado de México
The film opened at #1 at the North American box office making $20,108,829 USD in its opening weekend, although the film had a 39% decline in earnings the following week, it was enough to keep the film at the top spot for another week. Ultimately, the film earned $147.8 million worldwide.
The film holds a 56% rating on Rotten Tomatoes. The critical consensus states that "Though The Mexican makes a good attempt at originality, its ponderous length makes it wear out its welcome. Also, those looking forward to seeing Roberts and Pitt paired up may end up disappointed, as they are kept apart for most of the movie."
"The scenes between Roberts and Gandolfini make the movie special. ... Their dialogue scenes are the best reason to see the movie."
"Pitt and Roberts are good too – maybe better like this than if they were together. ... If it had been a Pitt/Roberts two-hander, there wouldn't have been room for Gandolfini's wonderful character, and that would have been a shame."
"'The Mexican' is sporadically entertaining. It works when Gandolfini is on screen; when he leaves, he takes the movie with him. ... From here, director Gore Verbinski, intercuts between two road movies, one of which (the one with Pitt) is downright boring".
"Roberts and Pitt are generally terrific. In 'The Mexican' they are horrid. ... Gandolfini is a star on the rise. His work in The Mexican is solid. Frankly, he's the only bright spot in this dark and pointless movie."
"Moviegoers who have seen The Mexican aren't coming out of cinemas talking about the romantic chemistry between Brad Pitt and Julia Roberts. They're talking about the presence of tough guy James Gandolfini in the unlikely role of a gay hit man named Leroy."