Her father was an engineer of public works, her mother, a painter and a musician. The grandfather, a Marseilles man, was a first-rate painter. The girl had three passions, the piano, dance, and painting; she has been awarded a first prize in the piano Conservatory of Reims. At the age of four already, she joined the troupe of Roland Petit, learned to dance en pointes with Maurice Béjart. In 1961, she passed the entrance examination of the National Conservatory of Paris. She received the first prize of Classical Comedy awards for the role of Sylvia in The Game of Love (Le Jeu de l’amour), an other of Modern Comedy for the role of the Sphinx in Jean Cocteau's The Infernal Machine, and yet another Tragedy Award for her role as the Infante in Le Cid.

Maurice Escande was behind her joining the Comédie-Francaise.
On stage, she found herself working in close collaboration with Robert Hirsch, Jean Piat, Jacques Charon, Berthe Bovy, and Annie Ducaux. She played Electra, Celimene, Elvira, Elmire, Junie, Berenice, Andromache, etc.
She played a role in Corneille's Le Cid, an experience which turned out to be not a happy one; yet the role she performed as Roxane in Cyrano de Bergerac was soon to send the previous disappointment she knew with Chimène into the realm of oblivion. If the Boulevard had offered her an extraordinary role, "I would have refused it,” she asserted without a shred of hesitation back in the sixties, the same way she had refused many cinema projects. In fact, she averred. "Nothing was more important for me than to succeed in joining the House of Molière."

On television, nonetheless, she played the roles of Marie-Antoinette and of the Marchioness Cibo in Lorenzaccio directed by the film-maker Franco Zeffirelli. She further played the roles of Lucrezia Borgia, Diane of Meridor, Shulmeister's spy, as well as Isabella of England in The Accursed Kings (Les Rois maudits). A sheer absolute queen, a tragic heroine par excellence and in essence, an empress, the blonde grace of the eternal feminine character, she enacted the roles of Mary Stuart, Elisabeth of England, the Queen in Ruy Blas, as well as Dona Sol in Hernani under the direction of Robert Hossein, the princess of Elide under the aegis of her master and choreographer Maurice Béjart in The Pleasures of the Enchanted Island (Les Plaisirs de l’île enchantée). She subsequently played the roles of the Countess in La Fausse Suivante (The False Lady’s Maid) directed by Jacques Lassalle, and, of course, the Countess in Beaumarchais’s The Marriage of Figaro staged by Antoine Vitez in 1989.

Taking risk does not frighten her nor does it prevent her from venturing out on tricky terrain: she interpreted Carmen in Jean Genet’s The Balcony (Le Balcon) directed by Georges Lavaudant. She has also played roles created by the contemporary authors David Mamet, Arrabal, and Pierre-Olivier Scotto. In 1993, after more than thirty years spent in the House of Molière, she presented her resignation to the then administrator Jacques Lassalle.
Immediately, however, she was cast to perform the role of Gertrude for Francis Huster who played and directed Hamlet at the Marigny Theater, with Michel Aumont aswell, and just the following year, L’Allée du Roi (The King’s Way). Geneviève Casile gracefully embodied all the figures of femininity of the great century. The lady has turned into the beacon of the luminous beauty radiating forth in the Golden Age of the French theater, enacting the roles of the queen, the martyr or even the whore, under the pen of Françoise Chandernagor. Mrs.Casile, now a sociétaire honoraire of the Comédie-Française, has systematically loved those tainted shady characters, and has been keen on Oscar Wilde’s refined dandyism and cynicism, of whom she has notably played Mrs. Erlynne in Lady Windermere's Fan, an acerbic and bitter social butterfly turning into a loving mother.

A woman painter, a real artisan, an actress of an unprecedented caliber, a humble worker, a first-class "nervous person" and the perfect venerable embodiment of the “queen's demeanor” expression, Geneviève Casile stands today in honor of a theater ablaze with the fires of tragic passion.