The movie is based on John Hughes' short story "Christmas '59", the second Vacation story to be published in National Lampoon's Magazine (the first was "Vacation '58", which was the basis for National Lampoon's Vacation (1983)). The Christmas story was printed in December 1980. The label on the home movie reel that Clark finds in the attic is labeled "Xmas '59," a further allusion.
According to an article on the making of Home Alone (1990) in Chicago Magazine, Chris Columbus states that he was the original director of this movie. Although he filmed some second-unit establishing shots (which he claims are still in the finished film), he left after two meetings with Chevy Chase and told writer/producer John Hughes, "There's no way I can do this movie. I know I need to work, but I can't do it with this guy." He was sent the script to Home Alone in its place.
After Clark Griswold unsuccessfully attempts to demonstrate his handiwork with the house Christmas lights to his family, he asks Rusty to help him check all the light bulbs again. Rusty looks at his bare wrist, pretending to have a watch, and excuses himself. Looking at a bare wrist and pretending to have a watch is one of Chevy Chase's trademark gags.
The house in which the Griswolds' neighbors, Todd and Margo, live is the same house where the Murtaugh family lived in all 4 'Lethal Weapon' movies (1987-98). The houses on this street are on the Warner Brothers Studios back lot. Ironically, in each Griswold 'Vacation' movie, Rusty and Audrey are played by a different pair of actors while in all 4 'Lethal Weapon' movies, the 3 Murtaugh kids were played by the same actors. Speaking of Danny Glover movies, two "Christmas Vacation" stars have immediate family who appeared in movies with Danny Glover. Juliette Lewis' father Geoffrey Lewis appeared in the Mel Gibson movie Maverick (1994) during the Danny Glover cameo. Randy Quaid's brother Dennis Quaid starred with Glover in Switchback (1997).
According to Randy Quaid, many of cousin Eddie's characteristics (most notably the clicking of the tongue) were based off a guy that Quaid knew from when he grew up in Texas years ago who had similar traits.
Near the end of the film, Rusty says, "I told you we should have gone to Hawaii!" In the first National Lampoon's Vacation (1983), when asked where in the world he would like to go the most, Rusty said Hawaii.
After failing to get the Christmas lights to work one last time, Clark Griswold takes his frustration out on the plastic decorations in the front yard. Chevy Chase actually broke his pinky finger while punching Santa Claus. He resorts to kicking and clubbing the decorations after that. The film kept rolling and the take was used.
When Clark and Cousin Eddie are talking in the living room, they are drinking egg nog out of Wally World mugs. Wally World was the destination of the Griswold's in the original National Lampoon's Vacation (1983).
Cousin Eddie explains to Clark that his older kids couldn't make it because his daughter was "at the Clinic getting cured off the Wild Turkey" and his son was preparing for his career as a carnival worker. This is a reference to Cousin Vicky and Cousin Dale from National Lampoon's Vacation (1983). Cousin Vicky would return once again in the following film, Vegas Vacation (1997), as well as Ruby Sue from this film (though played by a different actress).
When Eddie barges in the house with Clark's boss, Ellen jokingly tells him this is the family's first kidnapping, which is actually wrong. In National Lampoon's Vacation (1983), Clark holds the security guard at Walley World hostage and forces him to take the family on the rides.
When shopping with Clark, Eddie asks Clark if it was his company that "killed all those people in India". He is referencing the Bhopal disaster, also known as the Union Carbide disaster, in which leaks from a Union Carbide pesticide plant escaped into the air. Thousands of people died and many more were sickened.
The Warner Brothers back lot used for the neighborhood in which the Griswolds live is the same as the one used on The Middle (2009), which featured Brian Doyle-Murray (Mr. Shirley) in a recurring role as Mr. Ehlert and Doris Roberts (Frances) in a recurring role as Ms. Rinsky.
When Clark and Ellen discuss their concerns over Eddie and Catherine not having any Christmas presents for their kids, Ellen says that Eddie has "been out of work for close to 7 years." In National Lampoon's Vacation (1983), Eddie mentions having been laid off from an asbestos factory, which would have been nearly 7 years before "Christmas Vacation" takes place.
Just before Clark gets locked up in the attic, he pulls out an old present from a hidden slot, and it contains a card that reads "Happy Mother's Day 1983, Love Clark". The first movie, National Lampoon's Vacation (1983) was released that same year.
Brian Doyle-Murray appears in two of the Vacation movies. In Christmas Vacation he plays Frank Shirley, Clark's boss. In the original National Lampoon's Vacation (1983), Murray plays the Kamp Komfort clerk where the Griswolds stop to stay on their way to Wally World.
John Hughes was asked if he wanted to write a new film for the Vacation series. He said he would only do it if he had a good story to use, as by this point the franchise was a Chevy Chase vehicle and there was little need for him to write a story. He found one called Christmas '59 from his time working at National Lampoon Magazine that he thought was good, so he agreed to write the script.
All the presents that are on the credenza when Clark goes in to give his to Mr. Shirley are identically shaped and likely the same gift. It is a desk organizer. When this movie came out, pen sets came in an L-shaped arrangement. The writing instruments were on the flat part and the raised section held post-it notes. Paper clips and other holders were also a possibility.
A Wal-Mart storefront appears in the film with an empty parking lot - at the time of the film's release Wal-Mart did not have their stores operating 24 hours. This began when the chain was remodeled a few years later and the company converted their stores to hypermarkets (similar to its Sam's Wholesale Club stores without the annual membership fees). In real life, the slang for Wal-Mart is Wally World (appropriating the name of the Walley World theme park from the first film when referring to a box retailer).
Cousin Eddie has a son named Rocky who appears wearing a Las Vegas shirt. Coincidentally, footage from this film appears in the film Rocky V (1990). Furthermore, the next film in the series was Vegas Vacation (1997).
When the grandparents arrive at the Griswolds' house, Frances says to Ellen, "Doesn't Nora look old?" Diane Ladd was only 53 years old when she played Nora Griswold in this film. The film was released in theaters only 2 days after Diane Ladd's 54th birthday.
In several outdoor scenes at the Griswold home a 1963 powder blue Lincoln Continental convertible can be seen parked out front. This was the last of the curved glass slab sides and is sought after by collectors. The 1964 Continental convertible had straight glass windows to provide more interior space.
The messenger who delivers Clark's Christmas "bonus" is wearing a jacket that reads "Speed Ball Messenger Service". "Speedball" is a street term for a drug cocktail of heroin and cocaine, the same mixture that killed John Belushi 7 years earlier.
When Clark shows his coworker Bill the brochure about the swimming pool he wants to put in his backyard, he is seen drinking coffee out of a Tasmanian Devil coffee mug. Miriam Flynn (Cousin Catherine) would later go on to play the voice of Taz's mother in the cartoon Taz-Mania (1991). Additionally, Taz' father on that cartoon was a parody of Bing Crosby, whose song 'Mele Kalikimaka' appears in this film and whom Griswold mentions along White Christmas (1954). Furthermore, John Astin, who played game show host Kent Winkdale in National Lampoon's European Vacation (1985), was the voice of Bull Gator on that cartoon.
In addition to Randy Quaid and Natalija Nogulich having the same date of birth, there are several other notable birthday coincidences among the cast. Nogulich was born on the first of October, while her onscreen husband, Brian Doyle-Murray, was born on the last of October. E.G. Marshall and John Randolph, who play Ellen's father and Clark's father, respectively, were both born in the month of June. Doris Roberts and Diane Ladd, who play Ellen's mother and Clark's mother, respectively, were both born in the month of November. Mae Questel and William Hickey, who play Aunt Bethany and Uncle Lewis, were both born in the month of September. Marshall and Miriam Flynn were both born on June 18.
When Clark and Eddie talk about Eddie's children, Eddie calls the Tilt-a-Whirl ride the "Tilty-Whirl," a mistake quite in line with his rather simple-minded personality. A common slang name for the Tilt-a-Whirl is the "Whirl and Hurl."
Brian Doyle-Murray and Natalija Nogulich, who play husband and wife in this film, are the only natives of Chicago, Illinois (where the movie is set, even though it was filmed in California) among the film's cast. All other cast members were born outside Illinois. They also both guest starred in season 3 (2013-14) of 2 Broke Girls (2011).
The trivia items below may give away important plot points.
The scene where the cat bites on the Christmas lights cord and gets electrocuted was nearly cut from the movie. Prior to the first test screening, the studio executives wanted the scene taken out, fearing that it might offend some viewers, but producer Matty Simmons begged them to leave the scene in and they eventually gave in to his request. After the first test screening, the test audience scored the cat electrocution scene as their No. 1 favorite scene throughout the entire movie.
When Clark's boss is kidnapped and brought into the house, Ellen says, "This is our family's first kidnapping", similar to her line in the first National Lampoon's Vacation (1983), "This is our first gun."