The daughter of a wealthy and prominent attorney and judge, Hicks attended Simmons College and received her qualification as a teacher from Wheelock College. She worked as a first grade teacher in Brookline, Massachusetts prior to marrying in 1942. After the births of her two children, Hicks returned to school and completed a Bachelor of Science degree at Boston University in 1952. In 1955, she received a JD from Boston University Law School, attained admission to the bar, and entered into partnership with her brother as the firm of Hicks and Day.