Hardy, who was originally from Brooklyn, New York, was of Irish descent. She won several beauty pageants during her early years, including Miss Brooklyn, Miss Coney Island and Miss New York Press Photographer. She also appeared on the cover of Look Magazine. She began her entertainment career in New York City, performing at the Copacabana nightclub with such well-known performers as Danny Thomas and Jimmy Durante.
She met her future husband, actor Richard Egan, in 1956. The couple married in June 1958 and remained together until Egan's death in July 1987. The couple had four daughters - Patricia, Kathleen, Colleen, and Maureen Egan, a writer and music video director, as well as a son, Richard Egan, Jr., who founded Vagrant Records,
Hardy moved from New York to Los Angeles to pursue a film and television career. She was cast in several 1950s television episodes including two appearances on Perry Mason: as defendant Claire Olger in the 1958 episode, "The Case of the Haunted Husband," and as Jo Ann Blanchard in the 1959 episode, "The Case of the Startled Stallion." She also appeared in the series' State Trooper, The Loretta Young Show, Lassie and Schlitz Playhouse, in which she co-starred in an episode with James Dean. Her film credits included Girls in the Night in 1953 and Don't Knock the Rock in 1957.