Jon Favreau is directing the live action film from a script by Justin Marks.
The 10-year-old Sethi, from New York, was chosen from among thousands of kids who auditioned for the role in the U.S., the U.K., New Zealand and Canada.
“The Jungle Book” will be Sethi’s first acting role.
“Casting is the most important element of any film and finding the right kid to play Mowgli was imperative,” Favreau said in a statement. “Neel has tremendous talent and charisma. There is a lot riding on his little shoulders and I’m confident he can handle it.”
Casting director Sarah Finn described Sethi as embodying “the heart, humor, and daring of the character. He’s warm and accessible, yet also has an intelligence well beyond his years and impressed us all with his ability to hold his own in any situation. Even though he has no professional acting experience, his natural charisma and instincts jumped out at us.”
Sethi will be the only actor seen on screen in the film, with the rest of the characters created as computer-generated creatures.
Disney will release “The Jungle Book” on Oct. 9, 2015.