As noted on a featurette, Jackie Chan was the one who came up with the "jacket" routine as a means of teaching Dre Kung Fu moves.
Producer Will Smith said Jackie Chan was held in such high regard in China that he was able to use his status to help with many aspects of the production, such as getting permission to shoot in certain locations for filming.
Mr. Han (Jackie Chan) and Mr. Li (Rongguang Yu) stare off with each other more than once, but never get into a physical entanglement. The two actors fought each other in Shanghai Noon (2000).
The first movie to shoot in The Forbidden City since Bernardo Bertolucci's The Last Emperor (1987).
The style of Kung Fu that the woman standing on the dragon's head is practicing (at the temple, before the dragon well) is Crane Style Kung Fu. Practitioners of this style are very adept at balancing on one foot, as a crane does. It is interesting to note that she is controlling a cobra (likely in the same style as a snake charmer). This could possibly be a nod to The Karate Kid (1984), in which Daniel defeated a member of the Cobra Kai dojo by using the "Crane technique".
The U.S. title for this movie was kept as "The Karate Kid", to maintain the connection to the earlier movies on which it is loosely based, even though this movie takes place in China, and the martial arts used are forms of kung fu. The difference is referenced in the movie when Dre's mother describes a team as practicing karate, and Dre quickly corrects her.
For The Great Wall sequences, all of the camera equipment had to be hand-carried, as helicopters were not allowed. The helicopter shots were finally achieved before sunset. The wait was due to military exercises in the area.
After Dre (Jaden Smith) and Mr. Han (Jackie Chan) climb the mountain, when they enter the temple, we see people in white clothes moving slowly and methodically, as if dancing. The martial art they are practicing is Tai Chi Chuan (literal translation "Supreme Ultimate Fist").
Director Harald Zwart is true to his city's football team. He hides the logo of the soccer team: Fredrikstad Fotballklubb (FFK) in every movie he makes. In this movie, you can find it on the championship doctor's jacket as a small pin.
Several scenes were cut and trimmed for the mainland Chinese release, including the curtailing of scenes with bullies and the removal of a kissing scene.
The final tournament was shot at the Feng Tai Sports Arena in Beijing over a period of eight days with over eight hundred extras.
Before the tournament, Han (Jackie Chan) gives Dre (Jaden Smith) a shirt in which to compete. Dre comments that the shirt is just like one that Bruce Lee wore. One of Jackie Chan's early breaks in movies was as a stunt coordinator in Lee's movies. Chan also had small parts in The Chinese Connection (1972) and Enter the Dragon (1973).
Despite the title, there is no karate in the film. Instead it features kung fu, a martial art more relevant to the movie's location of China.
Sony considered changing the title to "The Kung Fu Kid", but this idea was nixed by producer Jerry Weintraub.
At the beginning of the movie, one of the markings on Dre's wall says 7/8/07-9th birthday. This is the actual ninth birthday of Jaden Smith, who plays Dre.
Mr. Han can be seen doing the famous "wax on, wax off" scene from The Karate Kid (1984), just after Dre begins his training.
Ralph Macchio, the star of the original Karate Kid film declined the offer of a cameo in this film.
In the scene where Cheng (Zhenwei Wang) and his friends are bullying Dre (Jaden Smith) and kicking around his books and backpack, Cheng is wearing a shirt that is very similar to the shirt Daniel (Ralph Macchio) wore during the tea ceremony and storm scenes in The Karate Kid Part II (1986).
Jaden Smith rides his skateboard as a lefty, but when he's drawing the picture of the lady and the snake he's writing with his right hand.
The martial arts schools mentioned at the climactic "Open Kung Fu Tournament of Champions" are: 1. The Fighting Dragon School 2. The Thousand-Hand Team 3. The Wu-Dao School 4.. The Crane Wu-Shu School 5. The Twin-Dragon Wu-Shu School 6. The Seven-Stars School (omitted from final draft of screenplay) 7. The Dancing Lion School (omitted from final draft of screenplay)
Feature film debut of Luke Carberry, as Dre's new friend in Beijing. He was an international student studying Mandarin when Harald Zwart discovered him and personally offered him the role, which he gladly accepted. His sister, Chloe Carberry, also appears in the film as an extra in the school scenes. She appears in 3-4 shots.