After three years at the University of Iowa, she came to New York City to study acting at the American Theatre Wing and made her professional debut in summer stock in Pennsylvania. She acted at the Cape Cod Playhouse, appeared in a touring production of Idiot's Delight with Nina Foch, performed in television programs produced in New York, and danced at the Copacabana nightclub.
She is best known for her portrayal of Mary Henry, a church organist haunted by specters, in Carnival of Souls (1962), a low-budget horror film that has developed a cult following. She also appeared in The Curse of the Living Corpse (1964).
Hilligoss was married to actor Nicolas Coster, with whom she had two children. They divorced in 1981.
- Naked City, Episode: "Hold For Gloria Christmas" (1962)...Mrs. Harris