The sound effect used by the jack-in-the-box is the same sound effect used by the laughing hyenas at the Magic Kingdom at Disney World in Orlando, Fl. And was also used in the 1955 Disney movie; "Lady and the Tramp" for the laughing hyenas in the zoo.
On the final day of shooting in New York, it was just the director, Will Ferrell, and a camera man driving around the city looking for locations to shoot. They would jump out and ask pedestrians if they would be willing to be extras for some quick cash while Ferrell paraded around acting like Buddy. Much of the montage when Buddy first arrives in New York was filmed then, such as when he is getting his shoes shined and jumping between traffic.
The design for Santa's Workshop as well as the Elf uniforms come from the original Rudolph, the Red-Nosed Reindeer (1964) animated special. The Elf uniforms completely mirror the ones from the TV special. Most of the animals in the North Pole are also designed to look like the same form of stop motion animation used in Rudolph.
Buddy's 12-second belch was supplied by voice actor Maurice LaMarche, best-known for his cartoon character, "The Brain", from Pinky and the Brain (1995), and who also did the operatic belching in Animaniacs (1993) as "The Great Wakarotti". LaMarche also worked with Will Ferrell on the animated series, The Oblongs (2001).
The brief TV news clip showing Buddy walking in Central Park (just before Buddy's dad and brother find him), and the still picture of Buddy in the news clip, closely mimic the famous 1967 film of an alleged Bigfoot ("Patty") taken by Roger Patterson and Robert Gimlin.
When Buddy goes to Gimbels to ask Jovie out on a date the song we hear playing over the loudspeaker is "Christmas Island" sung by Leon Redbone. Redbone also provided the voice of Leon the snowman at the North Pole.
Near the end, when Santa is showing Michael his nice list, all of the people on Santa's list worked on the movie: Victoria Down (key makeup artist) wants an English riding saddle with leathers and a crop; Drew Davidson (chief lighting technician, as Andrew Davidson) wants Rock-em Sock-em robots; Andreas Nieman (assistant property master, as Andy Nieman) wants a complete set of titanium drivers and a new golf glove; Nathan Tichenor (co-production coordinator) wants an Apple iBook with 1 gig hard drive and a built-in CD burner; Michael Hobbs is a character in the movie; Jimmy Miller (executive producer) wants a Hot Wheels turbo ultra race track with six cars, power launcher and track cleaner and Penny Gibbs (unit production manager) wants an Old MacDonald Farm Kit with Battery Operated Tractor and a Remote Controlled Cow-Tipper.
When baby Buddy is put in his crib on Christmas Eve, the nun at the orphanage gives him a bottle and leaves. While we now know that this is a dangerous practise, at the time that the scene was set, this was common. Parents and caretakers did not know of any risks, as physicians did not advise against it.
When she first meets Buddy, Jovie asks, "Did Crumpet put you up to this"? Crumpet is the name David Sedaris called himself while working as an elf, as recounted in his Christmas story anthology "The Santaland Diaries." David Sedaris's sister, Amy Sedaris appears in the film as James Caan's assistant, Deb. The usage of the name Crumpet may refer to Sedaris or may be a coincidence.
Zooey Deschanel performs three songs in this film. One of them is "Baby, It's Cold Outside" which she later made an official recording of, with her indie duo She & Him, released on their album "A Very She & Him Christmas" released in 2011.