His son, Marc "Doc" Simont, said his father died Saturday after a short illness.
In 1957 Simont won the Caldecott Medal, one of the top honors in American children's literature, for illustrating "A Tree is Nice," which was written by Janice May Udry.
He illustrated close to a hundred books, working with authors ranging from Margaret Wise Brown to James Thurber. He also won Caldecott Honor awards a half century apart, in 1950 and 2003.
Simont was born Nov. 23, 1915 in Paris. His parents were from Spain's Catalonia region and his father, Jose Simont, was a magazine illustrator.