He was born in Manhattan, New York City on April 27, 1901. He grew up in the Harlem area of Manhattan. His father was a prosperous dentist and his mother was May Doty. The family resided at 823 West End Avenue in Manhattan. Long's father was a keen fisher and hunter, and Long accompanied the family on annual summer vacations from the age of six months to 17, usually in the Thousand Islands region on the Canadian shore, about seven miles from the village of Gananoque. When he was three years old, on one of these vacations, Long fell into the river at the end of a long pier and contracted pneumonia