Noted artist Samir Mondal made three paintings for Aamir Khan for this film and did not charge anything for them. His works normally sell in the range of Rs. 100,000 to 700,000, depending on the size of the painting.
Aamir Khan received special permission from Amitabh Bachchan to use Abhishek Bachchan's experiences in the film. The reference is made in terms of Abhishek being one of the most successful stars and how he came to star in the blockbuster Dhoom (2004), overcoming the dyslexia that he had during childhood.
Darsheel Safary, the child artiste of the film, had to face a lot of opposition from his school when he was shortlisted for the film. The fact that he would have to miss school for such a long period did not go down well with the school authorities. However, Aamir Khan insisted that only Darsheel play the character, so he came up with a solution to fix the problem. He personally assured the school authorities that Darsheel's studies wouldn't be hampered with. Aamir arranged for personal tuition for Darsheel all through the academic year so that he wouldn't miss his exams. He also funded his studies as well as his educational expenses.
The house where Ram (Aamir Khan) places Ishaan's scratch-built boat/airplane model on his side table next to his own parents' photo is Aamir Khan's actual house in Panchgani. The actor bought some land there to develop.
Legendary actor Guru Dutt's younger sister and 'Kalpana Lajmi''s mother, 75-year-old Lalitha Lajmi, made her acting debut with this film. Lalitha, who is a noted painter and teacher, appears in a cameo role in which she plays herself. She shot it in November 2006 at Panchgani. She is seen as a chief guest who hands out a prize to the protagonist Ishaan Awasthi (Darsheel Safary).
Darsheel Safary, the 11-year-old star of the film, is a part of Shiamak Davar's dance troupe. During one of the classes, he saw a poster that read, "Hunting for a naughty kid. If you're selected, you will get a chance to act with Aamir Khan." He thought that it would be great if he was able the film. During the same class, Amole Gupte spotted him and asked him to go for an audition. Eventually, he got selected.
In the scene where Vipin Sharma hits Darsheel, Vipin was hesitant and couldn't hit him properly as Darsheel would start laughing so finally Aamir came with a solution, he wore Vipin's shirt which was sweaty and hit Darsheel facing his back to the camera.
Deepa Bhatia stated in an interview with The Hindu that her original inspiration was not dyslexia but rather the childhood of Japanese filmmaker Akira Kurosawa, who performed poorly in school. Her goal was thus to explore the story of "a child who did not fit into the school stream." She referenced a specific moment in Kurosawa's biography where he began to excel after meeting an attentive art teacher, and noted that this scene "became the inspiration for how a teacher could transform the life of a student."
Claymation was used in the opening credits for three minutes and for all the important parts of Ishaan's life. A lot of transitions that take place, such as water changing into a spaceship, a fish changing into a jellyfish, and so on were created by Dhimant Vyas, who had done the storyboards for the movie Lagaan: Once Upon a Time in India (2001).
Aamir Khan did not direct the entire film. Ram Madhvani (who directed the Boman Irani Hinglish starrer Let's Talk (2002)) directed the song "Bheja Kum," which was shot in a school in Panchgani. This is duly credited at the beginning of the end credits of the movie.
The name Nikumbh, given to Aamir's character, was the name of Amole Gupte's (the creative director and the writer of this film) art teacher, the late Shri R. S. Nikumbh, who was also the principal of the Hansraj Morarji Public School.