Poussin was known as the “philosopher painter” for his carefully conceived ideas about painting, based on the theories of ancient philosophers like Plato and Aristotle. Art, he believed, should embody harmony, reason, and moral order, such that Agrippina does not flail with anguish but sits with her family in a stable pyramid of private grief.

One scholar characterized Poussin as a "Christian Stoic," and Death of Germanicus is the artist's first work with a stoical theme: the Roman general accepts his fate and maintains his honor and composure in the face of death.

The agitation of the troops is countered by three soldiers standing tall across the front of the scene. Poussin would frequently make small wax figures and arrange and rearrange them before settling on a composition.

Emotions crescendo across the scene in a carefully controlled sequence, building from the helpless weeping of the muscular soldier at the far left to the alert vigor of the middle soldier draped in red to the unflinching resolve of the armored commander swearing vengeance.

The climax of the picture is a triangle formed by Germanicus in his bed, the resolute commander, and the young Caligula, who wears a blue cape like his father’s avenger. Each holds up a finger in a meaningful gesture—the commander invoking the gods he swears by, Germanicus feebly pointing to his son and future emperor, and the awestruck child emulating the older man’s gesture.