Samuel Badisch Ornitz was born in New York City, the son of Polish Jewish immigrants. Raised on New York's Lower East Side, a setting that dominates two of his novels, he became committed to social causes at an early age. As a boy he attended a religious school and participated in programs at the Henry Street Settlement House. After a sporadic college education and a few odd jobs he chose a career in social work. As an employee of the Prison Association, which gave legal support and help to the poor, he had free access to New York's The Tombs prison, where he encountered firsthand the extreme results of social neglect and abuse. He later served the Society for the Prevention of Cruelty to Children as assistant superintendent.

In 1914 Ornitz married Sadie Lesser; they had two sons. His first novel, Haunch, Paunch and Jowl, published anonymously in 1923, became...