Born Nila Mac, she was an only child. She added a "k" to her name because she felt "Mac" looked like a nickname. However, some sources, including her obituary in "The New York Times", said her birth name was Nila MacLoughlin. Her mother, Margaret, was a dance instructor. Her father, Don Carlos, was a railroad engineer who died in a train accident when Nila was very young. After his death, she attended an Illinois finishing school, Ferry Hall in Lake Forest, and later took classes in both Arkansas City and Boston, financing her education by playing piano at her mother’s dance studio.