Accidentally Correct Writing: Roads in the Quechua Empire actually did have rest stops that provided food and lodging, but they were obviously nothing like the modern-day Greasy Spoon depicted in the film.
Acclaimed Flop: The film received decent reviews but failed to recoup twice its budget, grossing $89.3 million domestically and $169.3 million worldwide on a $100 million budget.
In the Japanese dub, Kuzco is voiced by actor Tatsuya Fujiwara, aka Shuya Nanahara and Light Yagami in the Death Note's live-action films. Likewise, the theme song guy is voiced by the late singer Hideki Saijo, who many anime fans would recognize him as the singer of the first opening theme of ∀ Gundam, "Turn A Turn".
In the Italian dub, professional comedians Luca Bizzarri and Paolo Kessisoglu dub Kuzco and Kronk respectively, and Yzma is dubbed by none other than the late Anna Marchesini, an Italian comedy legend.
In the Brazilian dub, Kuzco is voiced by Selton Mello (who ironically initally started his career as voice actor, providing voices for the Brazilian dub of movies like The Breakfast Club and The Goonies and even voiced Doofus Drake in DuckTales (1987)), Pacha is voiced by Humberto Martins, Yzma is voiced by Marieta Severo and Theme Song Guy is voiced by famous musician Ed Motta (who previously worked with Disney in The Hunchback of Notre Dame by singing the Brazilian version of "Someday", and the Brazilian dub of the songs from Tarzan).
The German dub has Michael "Bully" Herbig as Kuzco. At the time, he was almost exclusively known for his TV sketch show, so it almost counts as Retroactive Recognition. Herbig's first movie, which made him a household name, wouldn't be published until a year after Emperor's New Groove, but at this point, he's one of Germany's most well-known comedians. It was the other way round with Yzma's voice actress Elke Sommer, who was a star and something of a sex symbol in the 60s and 70s, but the film's target audience had likely never heard of her.
Christmas Rushed: The film was firmly set for a 2000 date, hence Roger Allers' resignation. The reason wasn't Christmas, though - it was rushed due to a Happy Meal deal with McDonald's.
In Norway, the film is given the Richard III-inspired title A Kingdom for a Llama, because the word "groove" doesn't really have a good equivalent. Some merchandise does name it after its original title however (with "style" replacing "groove"), though the former mentioned remains the most known.
The German title translates the same as the Norwegian one, probably because translating the original title would have sounded extremely forced.
The Hungarian title can be roughly translated as Mindless Empire or The Empire Gone Crazy.
The European French title translates as Kuzco, The Egotistical Emperor (albeit with a very familiar term for 'egotistical'). The French Canadian title instead goes for A New Kind of Emperor.
In Portugal, the title would be hard to translate in way that would be easy to understand so the film is simply titled Pacha e o Imperador, which simply uses the two main characters names as the title.
As seen in The Sweatbox, many involved were unhappy that the film got to be retooled.
As the story was first being overhauled, Eartha Kitt wasn't too keen on the changes made to Yzma. The original script gave her depth and nuance, while the ultimate version was a broad cartoon villain. Eventually, though, she warmed to the character's new incarnation.
Creator Cameo: According to supervising animator Nik Ranieri (who animated the opening scene), he provided Kuzco's sobbing in the opening in place of David Spade during the ADR process of the film.
Just about every song was deleted, except for one, with another played over the end credits. They're still on the soundtrack, though. There's a whole documentary, The Sweatbox, about the film's troubled production (see Troubled Production below) which puts a great deal of focus on these songs (which were written by Sting).
The most notable of which was Yzma's Villain Song, "Snuff Out the Light", which, while a fantastic song, was actually a necessary cut, because the plot changed and made the motivation and ultimate goal described by the song irrelevant. It is available on the official soundtrack.
Yzma would have sung a Dark Reprise to "Perfect World," but it was removed during post-production.
Dark Horse Victory: In Mouse Madness, which pitted all of the Disney Animated Canon in a tournament-styled poll, Emperor's New Groove won it all despite being a #9 seed. Defeating Beauty and the Beast by a score of 20-10 in the second round set the tone for its run. The hosts of the podcast were just as surprised as anyone.
David Spade was in his thirties when he voiced the teenage Kuzco.
Sting suggested Tom Jones sing "Perfect World" under the assumption that Jones was younger than him. Jones is actually 12 years older than Sting.
Deleted Scene: After Kronk stuffs Kuzco in a bag and loses him in Pacha's cart, there was a scene where Pacha is standing in the middle of a giant model version of his village when Kuzco's army destroys it as practice for when they destroy his real village. This scene was fully colored before it was cut for being too dark and serious for the film.
The candle-holder in the dinner scene depicts Huaca, a sentient amulet character who got cut in the overhaul.
Yzma was originally intended to be obsessed with youth. In the sequel, her scheme involves getting rich by selling (fake) youth potions.
Dueling Movies: Against two films, to boot: The Road to El Dorado from DreamWorks, and Doraemon: Nobita and the Legend of the Sun King from Japan, all three of which take place in Mesoamerica. Disney themselves released Atlantis: The Lost Empire to go up against El Dorado. New Groove did win since it got better reviews and El Dorado bombed and sunk that franchise immediately. Legend of the Sun King as part of a wider franchise became the highest-grossing film at $32 million, but obviously it pales in comparison to the $169 million Emperor earned due to not being released outside of East Asia (since the series it's part of is unknown outside of the region).
DVD Commentary: It's mainly Producer Randy Fullmer and Director Mark Dindal commentary, but they're also joined by Art Director Colin Stimpson, Character Designer Joseph C. Moshier, Head of Story Stephen Anderson, Kuzco Animator Nik Ranieri, and Pacha Animator Bruce W. Smith.
The film started out as a Prince and Pauper film called Kingdom of the Sun in 1994, described by Lion King co-director Roger Allers as an "epic picture mixing elements of adventure, comedy, romance and mysticism". It would have been in the traditional style of Aladdin and Beauty and the Beast. The plot would've involved a greedy, selfish emperor who finds a peasant who looks just like him, so the emperor swaps places with the peasant for fun. Meanwhile, the evil witch Yzma has plans to summon the evil god Supai and capture the sun so that she may retain her youth forever. Discovering the switch between the prince and the peasant, Yzma turns the emperor into a llama and threatens to reveal the pauper's identity unless he obeys her. The emperor learns An Aesop about humility, and ends up loving a llama herder named Mata. Together, she and the emperor set out to stop Yzma's evil plans. Sting was signed on as the song composer. Disney execs thought that due to the poor critical and commercial reception of Pocahontas and The Hunchback of Notre Dame, both of which were serious dramatic musicals in the vein of Sun, the film would be unsuccessful. Compounding this was the fact that the release date had been firmly set at the year 2000, and by 1998 it was clear that production would not wrap up in time. Disney execs ordered production on Sun to be halted. Almost all the original plot points and characters were scrapped. Most of Sting's compositions were cut as well. The film became transformed into a "Looney Tunes meets The Muppets"-style slapstick buddy comedy. While the end result was warmly received by critics, who found it a breath of fresh air compared to most of Disney's fare, animator Andreas Deja, who supervised animation on Yzma during Sun, was displeased with what the film was reworked into, and left to work on Lilo & Stitch before the retool. Allers was also disappointed with the final film, calling it a "simple slapstick comedy", and saying that if he had had more time, he could've made the film according to his original visions.
On the DVD commentary, director Dindal grumbles about a minor example, claiming an executive at Disney forced him to include a particular The Wizard of OzShout-Out.
Fan Nickname: The final product is referred to as the "Dindal Cut" to help differentiate it with the "Allers Cut".
Irony as She Is Cast: When called upon to sing the theme song for Kuzco that he had written, Sting said that a then-50-year-old wouldn't do that song justice and that it was suited for someone younger and hipper. The filmmakers went with Tom Jones, who is ten years older than Sting.
For the Brazilian dub of Kronk's New Groove, Peterson Adriano replaces Selton Mello as the voice of Kuzco, Mauro Ramos replaces Humberto Martins as the voice of Pacha and Geisa Vidal replaces Marieta Severo as the voice of Yzma. Peterson, Mauro and Geisa would later reprise the roles for the dub of The Emperor's New School, with Peterson later in the series being replaced by Marcos Souza as the voice of Kuzco.
The same happens in the Japanese dub, as Showtaro Morikubo has to do double duty on replacing both Tatsuya Fujiwara from the first film (and also reprising that role from the dub of the TV series) and Yuuki Tokiwa as Tipo.
There's a rumor that, at one point, the production got so out of hand that Michael Eisner stormed into a story room, got in the director's face, held his thumb and forefinger an inch apart and yelled "You are THIS close to getting canceled!" before storming out.
Related to Troubled Production: Mrs. "Sting", Trudie Styler, filmed a (slightly unfinished) documentary on the film's production, The Sweatbox. It was screened once, but since Disney owns this document of chaos, they make sure it never gets released (very likely due to there being a large amount of swearing in it), though it was briefly leaked on the internet in March 2012. Platypus Comix did a review when they got hands on the workprint, which can be found here.
Wag the Director: Sting, who was already annoyed about having to stay on a project for which he'd already exhausted all of the time he'd set aside, nearly left the project when he objected to the original ending where Kuzco spared Pacha's village, but still built his water park on the hill next to his. He wrote to the producers that this meant that Kuzco hadn't learned anything, not to mention went against his personal beliefs about the environment, to which they agreed and had the necessary changes made.
Kuzco was originally named Manco until someone realized that it was also the Japanese word for "pussy".
In the original Kingdom of the Sun, Pacha would've been voiced by Owen Wilson. He recorded all his dialogue but when the film was retooled, his voice work was thrown out.
Marc Shaiman originally scored the film but had his work rejected after a test screening and was replaced by John Debney. Shaiman's work can be heard in The Sweatbox (the making-of documentary on the film and its Troubled Production) and in the video game where the clips from the movie are used. He describes his take as having too much Mickey Mousing.
Originally, Kuzco was going to have a love interest named Mata, to be voiced by Laura Prepon. For the finished film, the character was scrapped and her name was given to the waitress.
Pacha was also going to gain a love interest, Nina, voiced by Carla Gugino.
The movie as made was supposed to end with Kuzco building Kuzcotopia on a hill further away from Pacha's village and inviting Pacha and his family to stay in it, before Sting pointed out that if Kuzco still built his mansion after all his experiences he wouldn't really have learned anything.
Changing the typical Disney Renaissance-era epic into a screwball comedy was nothing but this. Disney's staff was sick of doing blockbuster musicals and fought for a smaller, more experimental film when Kingdom of The Sun was rejected. In turn, a number of the original team who weren't fired willingly left, believing that the retool would trivialize their work.
In the Mexican Spanish dub, Kuzco was originally planned to be dubbed by a soap opera actor (Arath de la Torre, to be exact), and while he did finish the dub, and was payed for it, it was never used because Walt Disney's Mexican branch didn't like his performance and, probably to avoid another sub-par performance with the main character (just like they did with the dub of Hercules), he was replaced with Jesús Barrero, who originally only dubbed him in the trailers.
Write What You Know: When the gag of baby Kuzco was added to the beginning of the film, Nik Ranieri, his lead animator, begged the directors to let him animate it because of how much it reminded him of his two toddlers and newborn at home and wanted to apply his observation of them to animation. Every frame of that gag is based on his kids. The design was specifically based on his daughter Belinda.