Satyam, who passed his class 12 exam last year, secured an impressive all-India rank of 679.
"We are proud of him. He has done something special at this age," Satyam's father Sidhnath Singh, a farmer said.
IIT-JEE (Advanced) results for admission into IITs were declared on Friday.
According to IIT-JEE website, Sahal Kaushik from Delhi was the youngest person to have cracked the exam in 2010 at the age of 14. But now this record is held by Satyam.
"Now Satyam is the youngest to crack the IIT-JEE," an IIT official said.
Satyam, who hails from Bakhorapur village in Bhojpur district, had last year qualified for admission into IIT at the age of 12-and-a-half years after he got a special permission from the Central Board of Secondary Education (CBSE). He had then secured an all-India rank of 8,137.
Not satisfied with his low rank, he appeared for the IIT-JEE preliminary examination this year again and qualified.
"Satyam has improved his rank by his hard work and determination," his father said.
He appeared for the entrance examination in Kota, Rajasthan, where he had been studying. He was one of the 150,000 candidates who appeared for the examination this year.
Earlier, Satyam Kumar had said he wanted to establish a software company on the lines of social networking website Facebook.