The author had a stroke on Friday, according to his longtime friend and caretaker Lynn Caponera. Caponera was with Sendak when he died.
Sendak revolutionized children's literature, evoking powerful images with his words and pictures. He was awarded the prestigious Caldecott Medal for the 1964 book "Where the Wild Things Are," which tells the story of a boy who journeys through his imagination after being sent to bed without dinner. The book became a hit film in 2009 and was read by President Barack Obama at the Easter Egg Roll.
"He was kind of the first to break the rules a little bit with children's literature," said Morgan Turnage of Vroman's Bookstore.
Known as much for his illustrations as his writing, children pass by murals of his characters every day at his namesake school in North Hollywood.
Sendak received a National Medal of the Arts in 1996 from former President Bill Clinton. Sendak also created costumes for ballets and operas, including "The Nutcracker." His illustrations for children's works such as "A Hole Is To Dig" and "Little Bear" launched his career. He would later serve as a producer for the animated television series of "Little Bear."
Sendak worked and resided in Ridgefield, Conn.
The Associated Press contributed to this report.