Romay was born in Barcelona in 1954. Following graduation from high school, she studied the arts, married actor/photographer Ramon Ardid/ Raymond Hardy (they later divorced in 1978), and began acting in stage productions. She began appearing in Jesús Franco's films from the time that they met in 1972. She appeared in more than a hundred feature films, most of them directed by Franco. Among the better known of her horror films are The Bare Breasted Countess (a.k.a. Female Vampire) (1973), Barbed Wire Dolls (1975) and Jack the Ripper (1976).

She took the name Lina Romay from the actress and jazz artist from the 1940s. Although Romay was listed in the credits of several of Franco's films as a co-director, actor Antonio Mayans stated in a recent interview that Franco used to credit her in that manner for business reasons, although she never actually co-directed any of their films together. She did however contribute occasional story ideas and assist in the editing of some films and trailers.