Lenore Leslie Lonergan was the daughter of actor, ‘Lester Lonergan, Jr (1893-1958)’ and opera singer, Julia Mary (Juliet) McIntyre-Lonergan (1889-1942). Her brother, Lester Lonergan III (1924-1968) was also an actor. Her paternal grandfather was Irish born actor, Lester Lonergan (1869-1931). She was raised in New York City and attended the Professional Children’s School along with her brother. She made her stage debut in at the age of 6 in “Mother Load” starring Melvyn Douglass and went on to play the role of Fluffy Adams in Junior Miss by Jerome Cherdov and Joseph Fields.