In 1963 Bernard enlisted in the French navy as a trainee engineer, graduating first in his class one year later. During his naval service, Giraudeau served on helicopter carrier Jeanne d'Arc from 1964-1965, and again from 1965-1966. Subsequently, Giraudeau served on the frigate Duquesne and on the conventional aircraft carrier Clemenceau before leaving the navy to begin his career as an actor.