LaNasa was born in New Orleans, Louisiana, the daughter of Anne (née Hardin) and Dr. James J. LaNasa Jr., a surgeon.
She began dancing at the age of 12, and at the age of 14, she was admitted to the North Carolina School of the Arts in Winston-Salem, North Carolina. After an apprenticeship with Milwaukee Ballet, LaNasa danced with Salt Lake City's Ballet West and the Karole Armitage Ballet.