William H. Macy said that when the film was shown in European film festivals, afterward people mostly discussed the script and the characters, but when the film was shown at American film festivals, people mostly discussed how good Maria Bello looked in her nude scenes.
According to the director's commentary, William H. Macy was given three suits to wear during the film. During scenes where his character Bernie was hapless and unlucky, he wore a suit that was two sizes too big for him. During scenes where his luck was starting to turn around, he wore a suit that was one size too big for him. After he falls in love and is extremely lucky, he wears a perfectly tailored suit. Also, as Bernie's luck improves, the lighting surrounding him gets brighter, and his shirt and tie go from dark and subdued to bright and colorful.
The entire film was shot in Reno over three weeks, mainly inside a Reno Hotel Casino, The Golden Phoenix, that was being remodeled. The Golden Phoenix is on Sierra Street. The hotel was previously the Flamingo Hilton Reno, and prior to that was Del Webb's Sahara Reno Hotel.
Bernie's Room 104 is located at the Town House Motor Lodge, 303 West Second Street, in Reno, Nevada. The film crew put another motel sign ("Bettor Life") over the Town House sign for filming the movie. The EZ Mini Market where Bernie shops is also at the Town House Motel. The Room 104 interiors were shot at the studio. The pool is still empty, even in the summers. The Town House is a quarter mile from the Golden Phoenix, at Second Street and Arlington in Reno.
This film originally received an NC-17 rating and was re-cut to achieve an R. The details of the rating dispute are documented in the film This Film Is Not Yet Rated (2006), which shows some of the deleted footage.
The Cooler (2003) contains at least one tribute to the films of Alfred Hitchcock. When Shelley is being shown the new jackpot machine during Bernie's "hot" scene, the demonstrator tells him he calls it Marnie, "y'know, 'cos she's one frigid broad!" This refers to Hitchcock's Marnie (1964), in which Tippi Hedren plays a woman who is very sexually reticent. In addition, the film's trademark extreme worm's-eye-view shots from beneath card tables (of croupiers pushing casino chips into extreme close-up) and floors (of the soles of Bernie's shoes) may be homages to The Lodger (1927), in which Ivor Novello is shot via a similar technique to increase tension.
When Bernie pulls up to his motel room, just prior to discovering Natalie's injuries following Shelly's visit to their room, the faulty neon sign for the EZ Mini Market is reflected in his car's windscreen. At one point it displays EZ Mark, a reference to the earlier story about how he and Shelly used to identify potential victims for a con, marking them with chalk. At the point Natalie confesses to having been paid by Shelly to get close to him, she calls Bernie and Easy (EZ) Mark.
The casinos demolished in the closing credits are: the Aladdin, the Sands, the Landmark, and the Dunes. The Dunes was bought and demolished in a giant pyrotechnic display begun by Steve Wynn when he fired a mock cannon from Treasure Island; in part he did it to insult The Dunes' former owners; the property became the Bellagio; Wynn has since sold all of his Mirage Resorts properties to MGM Grand and bought the Desert Inn, which he demolished to build Wynn Las Vegas. The Sands was where the Rat Pack held The Summit, a series of shows they did for fun while filming the original Ocean's Eleven (1960), an epoch that helped to define the Las Vegas that Shelly Kaplow mourns in The Cooler; The Venetian now stands on the Sands' lot. The Aladdin was rebuilt, but has performed poorly due to its similarity to all the other megacasinos, overbuilding in Vegas, and the slower economy. The Landmark's demolition can be seen in Mars Attacks! (1996); the property was used to expand parking for the Las Vegas Convention Center.
The movie is based near Fremont street, which is now known as the Fremont Street Experience in Las Vegas. It's the original Las Vegas casino area before the strip was developed. Only the aerial exterior shots were filmed in Las Vegas. The majority of the location shots were all filmed in Reno, Nevada.
The trivia items below may give away important plot points.
According to the director's commentary, the scene where Shelly breaks Larry's arm had to be re-shot. Director Wayne Kramer said the scene was shot out of focus. After having reviewed the footage, they had to re-shoot the scene, but actor Ron Livingston was already back in Los Angeles. Livingston flew back to Reno, Nevada just to re-shoot that one scene.