1. Screenwriter John Hughes wrote the entire script in just nine days after a bout of traveler’s anxiety.
Hughes’ son James wrote in Chicago magazine that the idea grew out of a hectic start to an August 1989 family trip to Europe. “Two weeks later, after returning home, he revisited the premise: What if one of the kids had been accidentally left behind?” James said.
2. Director Chris Columbus auditioned 200 children before casting Macaulay Culkin as Kevin McAllister.
“I think John [Hughes] knew all along that he wanted Macaulay in the movie. I thought he was great in Uncle Buck, but I owed it to myself as director to see other child actors. John said, ‘Okay, take your time, do what you need to do,’ ” Columbus said. “I ended up seeing 200 other kids, looked over hundreds of videotapes. Then Macaulay read, and you immediately knew this was the kid.”
3. The iconic John Williams score almost didn’t happen.
In the Home Alone director’s commentary, Columbus said the original composer he chose, Bruce Broughton, didn’t end up being available to score the film, although some teaser posters still have his name on them. There was no composer or score at all while most of the film was shot; Williams was sent a finished print of the movie, which he loved, so he decided to write the music for it.
4. The McAllister’s house is real, and it’s in Winnetka, Illinois, a suburb about 21 miles north of Chicago.
The family that lived there at the time stayed in their house during most of filming and reportedly loved it. Columbus said the family made hot chocolate for the cast and crew and would invite them inside.
5. But many of the interior shots of the house and other scenes of the movie were shot inside Chicago-area New Trier High School.
The school’s swimming pool was converted into the McAllister’s basement. The school was also used for the police station and some airport scenes.
7. Joe Pesci, who ended up portraying Harry, wasn’t used to acting in a family-friendly movie, and reportedly cursed often on set.
Columbus, who’d wanted to hire Pesci based on his roles in R-rated films like Raging Bull and Goodfellas, advised Pesci to say “fridge” instead of “fuck”. Columbus also noted in the director’s commentary that Pesci wasn’t always thrilled to be on a set where a child was the star of the movie.
8. John Candy shot his role in one 23-hour filming day.
He worked from 6 a.m. to 7 a.m., but even that wasn’t enough time for him to film a farewell scene with Catherine O’Hara, who played Kevin’s mom, when she arrives at her house.
9. And he improvised all of his lines, like a true Second City alum.
Candy’s improvised scenes with O’Hara, another Second City alumna, were so irreverent that many had to be cut because they were too lighthearted to be appropriate for a mom trying to reunite with her son.
10. Old Man Marley wasn’t originally part of the movie at all.
His role was created after the first script. According to Columbus, his name was inspired by Charles Dickens stories, as was much of the feel of the movie.
11. The scary furnace in the basement was actually just the work of two guys with strings and flashlights.
Columbus initially wanted the whole thing to come to life using CGI, but the movie’s relatively small $18 million budget didn’t allow for it.
12. Angels with Filthy Souls isn’t a real movie. Columbus shot it specifically for Home Alone using Ralph Foody, a real actor.
13. The Christmas ornaments that Daniel Stern, who plays Marv Merchants, walked on were made out of candy glass — and he insisted on stepping on them with bare feet.
He did wear rubber feet to walk through the snow in his outdoor scenes, though.
14. While rehearsing for the scene where Harry tries to bite off Kevin’s finger, Pesci actually bit Culkin, which left a scar.
15. Marv’s line, “Why are you dressed like a chicken?” was improvised.
16. And so was Kevin’s line, “You guys give up, or are you thirsty for more?”
17. The spider on Marv’s face was real, and they filmed that scene in one take — but Stern mimed the scream so he didn’t scare the spider.
21. It’s really, really, ridiculously popular in Poland.
Four million people tune into its annual Christmastime TV airing each year. It was one of the first western films shown in Poland after the fall of Communism in 1990, and is called “Kevin Sam w Domu,” or Kevin Alone in the House in Polish.
22. Columbus wanted to film two sequels at the same time right after the success of the first movie (so that Culkin wouldn’t noticeably age too much, a process Columbus used when directing his Harry Potter installments), but the studio wouldn’t let him.
24. And the picture of Buzz’s girlfriend is really a boy because Columbus didn’t want to make a girl feel bad about her looks.
Unless otherwise noted, all facts are from the Home Alone director’s commentary.