Ellen Conford was born in New York City, New York. She was a shy child, and gained a love of books while in elementary school, when she read up to eight books a week. She has loved writing since she was in the third grad. Encouraged by her teachers, she decided while still in grade school to become a professional author. In high school, she worked on the student newspaper and edited the school's humor magazine. In 1959 she attended Hofstra College (now Hofstra University), planning work as a proofreader and salesperson to support herself through college. On the first day of class she met fellow student David Conford, whom she married, and she subsequently dropped out of school.

In 1961 she had a son, and during his childhood she found a lack of quality children's books for him, which inspired her to begin writing books for children. Her first book, Impossible, Possum, was published in 1971. Since then, she has produced over 45 books for children. Her books have won the Best Book of the Year Citation, Best Book of the International Interest Citation, Best Book of the Year for Children, Parents' Choice Award, and more.