She is Coriolanus's mother and the most intricate female character in the play. From one angle, she embodies the ideal Roman matron: a deeply patriotic woman who has instilled in her only son the pursuit of honor through service to his country. Indeed, Volumnia proudly states that she would willingly see her son Coriolanus fall in battle if it meant contributing to his glory and Rome's well-being. However, her aggressive ferocity and thirst for blood make many modern readers uncomfortable. Her preference for the image of blood gushing from a hero's forehead over that of a mother nursing her child appears shocking and unnatural. She frequently expresses disdain for her daughter-in-law Virgilia's tenderness. When Virgilia inquires how she would feel if Coriolanus were to perish in battle, Volumnia answers that she would consider the noble reputation that survived him as a replacement for her son.

Volumnia's relationship with Coriolanus has sparked numerous questions among readers and critics. Some argue that her drive to see him adorned with military honors mirrors her own desire to be a warrior—a role that Roman society denied her. She is the first to suggest after his triumphant victory at Corioles that now there is only "one thing wanting" (II.i.201), referring to the consulship. Whether this position suits him is never questioned: it represents the pinnacle of her ambitions for him. Additionally, there are unsettling hints of incestuousness in Volumnia's remarks about Coriolanus. "If my son were my husband," she tells Valeria, she would take more joy "in that absence wherein he / won honour than in the embracements of his bed / where he would show most love" (I.iii.2, 3-5).

Her fervor is occasionally tempered by her pragmatism. She desires her son to be elected consul and strategically plans how this should be accomplished. The number of his wounds is significant, and at II.i.146-50, 153-54, she tallies them, highlighting the political significance of scars "to show the people" (II.i.147) when he seeks political office. She encourages her son to compromise his principles—the very ones she instilled in him—to secure the people's votes. Though she has taught him to scorn the common citizens and fiercely value his integrity, she implores him in III.ii to set those beliefs aside and pretend to be something he is not. Partly because he has been raised to be an obedient son, Coriolanus complies with her wishes.

Near the end of the play, she once again urges him to compromise his honor. She begs him to spare Rome, wanting him to act as a peacemaker, seemingly oblivious to the irony: she has raised and trained him to be a warrior. She declares that "no man in the world" has been "More bound to's mother" (V.iii.158-59) for his accomplishments, yet she claims, "Thou hast never in thy life / Show'd thy dear mother any courtesy" (V.iii.160-61). She shames him by kneeling before him—a startling reversal of ancient Roman customs, which dictate that children should revere their parents. She ends by depicting him as the cause of her potential death:

So we will home to Rome
And die among our neighbors.
…
I am hush'd until our city be afire,
And then I'll speak a little.
(V.iii.172-73, 181-82)

She seems unaware that if he withdraws the Volscians from Rome, it will likely lead to his demise. After Coriolanus acquiesces and explains to Volumnia the consequences of his concession, she falls silent. When the women return to Rome, they are met with a tumultuous welcome. Volumnia does not reply to the senator who praises her for her accomplishment.