Reputedly, Haley Joel Osment got the role of Cole Sear for one of three reasons. First, he was best for it. Second, he was the only boy at auditions who wore a tie. Third, director M. Night Shyamalan was surprised when he asked Haley Joel Osment if he read his part. Osment replied, "I read it three times last night." Shyamalan was impressed, saying, "Wow, you read your part three times?" To which Osment replied, "No, I read the script three times."
While in New York City auditioning for Bringing Out the Dead (1999), Toni Collette also auditioned for this film as an afterthought. She said the scene in the car toward the end of the film, which was the audition scene, was the scene that really drew her to the film.
Is one of only four horror films to receive an Oscar nomination for Best Picture; the other four that have received nominations are: The Exorcist (1973), Jaws (1975), and The Silence of the Lambs (1991).
This was the first of two movies that Bruce Willis owed Disney, after he caused another production, "The Broadway Brawler," to be shut down, due to him firing the director. He also was paid ten million dollars, half of his usual salary at the time.
To call the film a sleeper hit is to underestimate how low under the radar it flew before its release. In Entertainment Weekly's 134 film Summer Movie Preview of 1999, The Sixth Sense (1999) was not even mentioned on the list.
The Latin phrase Cole speaks in the church when he first meets Malcolm, "De profundis clamo ad te domine," translates to "Out of the depths, I cry to you, O Lord." These are the first few words of Psalm 130 in the Book of Psalms.
When Cole and his mother are sitting in the kitchen, there is a glass on the table that can only be bought in Philadelphia. It originally comes filled with Penn Maid sour cream, which is not readily available anywhere else.
Donnie Walhberg plays a character in this movie named 'Vincent Grey'. In 1998, just one year prior, he played a character named 'Mr. Grey' in the TV movie "The Taking of Pelham 123". In the 2003 movie "Dreamcatcher" he played a character named 'Duddits' who defeats and kills an alien antagonist named 'Mr Grey'.
The trivia items below may give away important plot points.
In the scene when Cole says the famous line, "I see dead people," the camera does a closeup on Bruce Willis's face. Producer Frank Marshall was worried that might have given the game away. It implied that Malcolm was a dead person. Fortunately, none of the audiences in the test screenings or afterwards picked up on it.
When Cole and Malcolm are entering Kyra's bedroom at her wake, Malcolm is standing directly behind Cole; however, when the camera cuts to the shadows on the floor as the door opens, we only see Cole's shadow. Another clue that Malcolm is actually dead. Also, on the doorknob, we can see the reflection of Cole's face but not Malcolm's face (although we probably can see his body).
While circling a passage in the notes, Bruce Willis does so with his right hand. Willis is actually left-handed; he learned how to write right-handed so that viewers wouldn't notice that his wedding band was no longer on his hand. Willis also draws the circle clockwise (like a left-handed person would), while most right-handed people would draw it counter-clockwise.
M. Night Shyamalan deliberately used the color red to depict when the world of the living and the world of the dead would cross over. If red was in a scene where that was not the case, he would change it. The door to the church where Cole and Malcolm first interact is red, and the statue Cole takes from the church has a red robe. The doorknob to Malcolm's basement is red. Cole's school uniform jacket is reddish (maroon); he is often approached by the dead people while at school and/or wearing his uniform. Anna wears a red dress at the restaurant where Malcolm is "late" for their anniversary. When Malcolm is watching his wife Anna in the shower and notices her prescription in the cabinet, it is in a reddish-brown container. Lynn Sear's nail polish is red when she is pointing out the white spots (ghosts) on all the pictures of Cole in the hallway. Cole's "free association" writing is in red ink; the writing presumably records things he has heard from the dead. At the birthday party, all the visible balloons are pastel-colored, except for the red balloon that floats up the stairway and leads Cole to the small closet. Cole is wearing a red sweater when he is attacked by the spirit in the closet. Cole's blanket at the hospital is reddish (pink) when he confesses to Malcolm that he sees dead people. The birthday gift Anna gives to Sean is in a red box, and she is wearing red when the two of them embrace and Malcolm breaks the shop door. When Malcolm listens to a taped session with Vincent, as he turns up the cassette recorder volume, the control numbers go from white to red. Kyra Collins appears in Cole's fort, and the blanket covering it is red. The box containing Kyra's VHS tape is trimmed in red and has a red-lined interior. The outfit worn by Mrs. Collins at Kyra's wake is bright red, and she is the only person wearing a bright color. In the video, the soup Mrs. Collins brings to Kyra is tomato soup, and the bottle of pine cleaner Mrs. Collins adds to the soup has a red cap on it. The bicyclist Cole sees next to the car is wearing a red helmet. The blanket that Anna Crowe covers herself with while watching the wedding video is red.
Throughout the movie, Malcolm never moves any objects (except the Latin dictionary), and he does not interact with anyone but Cole. For example, he never opens a door, the chair he sits in, in the restaurant with his wife, is already pulled out, and when he reaches for the check, his wife just beats him to it.
Though the movie is set in Philadelphia, the house in which the scene where Cole(Haley Joel Osment) is locked in a closet with the psychotic ghost is actually located in Pasadena, California. It has been seen in many other movies from the outside.