Leah Hager Cohen was born in 1967 in Manhattan, New York. Then the family raised in Queens and later in Nyack, New York, where she spent a large part of her childhood. Her father is Oscar Cohen, a superintendent at the school for the deaf, her mother who died in 2012 was a doula. Cohen grew up with a white biological sister and an African-American adopted brother. Her great-grandmother, Pearl, immigrated to America from Bukovina and threw herself from the window of a mental hospital when Cohen's grandmother was still a young girl.