Born in Lyon, France, Girardon began acting as early as 1956, and had a small but noticeable role as a deaf-mute beauty in director Luis Buñuel's La mort en ce jardin (Death in the Garden) (1956).

She is probably best known as an actress for her work in director Louis Malle's Les Amants (The Lovers) in 1958, and the 1961 Howard Hawks production of Hatari!

1963 proved to be her most active year, with several avant garde films to her credit including Pierre Kast's Vacances Portugaises (Portuguese Vacations), André Cayatte's experimental 'paired' films Jean-Marc ou La vie conjugale (Anatomy of a Marriage: My Days with Jean-Marc), and Françoise ou La vie conjugale (Anatomy of a Marriage: My Days with Françoise), and director Éric Rohmer's La Boulangère de Monceau (The Girl at the Monceau Bakery).

During the 1960s, Girardon became romantically involved with a married Spanish nobleman and occasional actor, José Luis de Vilallonga, whom she had first met on the set of Les Amants.

[3] By 1971, Girardon's acting career was over and after finally obtaining his divorce in 1972,[4] de Vilallonga ended their relationship to marry another woman, Ursula Dietrich.