In August 1965, Jane married her first husband, prominent French film director Roger Vadim. They tied the knot in a small ceremony at the Dunes Hotel in Las Vegas. At the time, Jane was 28; Roger was 10 years her senior and known for being a womanizer (Jane was actually his third wife).
By the time he married Jane — who moved to Paris in the hopes of pivoting her reputation as the "girl next door" to more serious, sexier roles — he had already had previous romances with other beautiful actresses like Brigitte Bardot and Cindy Pickett. He shared a son with French screen siren Catherine Deneuve, and a daughter, Nathalie, from a previous marriage with Danish actress Annette Stroyberg. Nathalie and Jane formed a sweet bond, and the then-teenager considered her a strong mother figure.