Adams was born in Manila in 1932, daughter of José Arrastia, the maternal great-grandfather of Enrique Iglesias. She reportedly never met her father. Her mother, Carmen "Miami" Salvador, was a hula dancer of Spanish and German descent. In her early teens, during the Japanese army's occupation of Manila during World War II, she became a spy for the Philippine resistance, carrying messages between guerrilla groups. She was later wounded by shrapnel during the Allied liberation of the island. She moved to the United States in 1948 and attended Rosemary Hall, a private school in Connecticut. She then went to New York to study dancing where she got a scholarship at the Katherine Dunham School of Dance. To avoid typecasting because of her name, she became known as Neile Adams.