Sendak was born in New York City in the borough of Brooklyn to Polish Jewish immigrant parents named Sadie (née Schindler) and Philip Sendak, a dressmaker.[3][4][5] Sendak described his childhood as a "terrible situation" due to the death of members of his extended family during the Holocaust which exposed him at a young age to the concept of mortality.[6] His love of books began when, as a child, he developed health problems and was confined to his bed.[7] He decided to become an illustrator after watching Walt Disney's film Fantasia at the age of twelve. One of his first professional commissions was to create window displays for the toy store F.A.O. Schwarz. His illustrations were first published in 1947 in a textbook titled Atomics for the Millions by Dr. Maxwell Leigh Eidinoff. He spent much of the 1950s illustrating children's books written by others before beginning to write his own stories.
His older brother Jack Sendak also became an author of children's books, two of which were illustrated by Maurice in the 1950s.[8]
Maurice was the youngest of three siblings. His sister, Natalie, was nine years older than he, and his brother, Jack, was five years older than he.[9]