She is Coriolanus's mother and the most complex female character in the play. From one perspective, she may be seen as the ideal Roman matron: a fiercely patriotic woman who has raised her only son to seek honor in the service of his country. Indeed, Volumnia proudly acknowledges that she would be willing to see her son Coriolanus killed in battle if it would contribute to his glory and Rome's welfare. However, her warlike ferocity and bloodthirstiness make many modern readers uneasy. Her preference for the image of blood spurting from a hero's brow over that of a mother nursing her child seems shocking and unnatural. She repeatedly expresses contempt for her daughter-in-law Virgilia's tenderheartedness. When Virgilia asks her how she would feel if Coriolanus were to die in battle, Volumnia responds that she would regard the noble reputation that lived after him as a substitute for her son.

Volumnia's relationship with Coriolanus has raised many questions among readers and commentators. Some believe that her determination to see him wreathed with military honors reflects her own desire to be a warrior—a role that Roman society would not allow her to assume. She is the first one to suggest after his glorious victory at Corioles that now there is only "one thing wanting" (II.i.201), that is, the consulship. Whether this is a suitable position for him is a question that does not arise: it would be the culmination of her ambitions for him. There are also disturbing elements of incestuousness in Volumnia's references to Coriolanus. "If my son were my husband," she says to Valeria, she would rejoice more "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 passion is sometimes offset by her practicality. She wants her son to be elected consul, and she carefully calculates how this should be achieved. The number of his wounds is important, and at II.i.146-50, 153-54, she adds them up, pointing out the political importance of scars "to show the people" (II.i.147) when he seeks political office. She urges her son to compromise his principles—the very ones she instilled in him—in order to win the people's votes. Though she has taught him to disdain the common citizens and to be fiercely proud of his integrity, she pleads with him in III.ii to set those things aside and pretend to be something he isn't. In part because he's been taught to be a submissive son, Coriolanus obeys her.

Once more, near the close of the play, she asks him to compromise his honor. Pleading with him to spare Rome, she wants him to be a peacemaker, apparently unaware of the irony: she has raised him and educated him to be a warrior. She asserts that "no man in the world" has been "More bound to's mother" (V.iii.158-59) for what he has achieved, and 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 to him—a shocking reversal of ancient Roman standards calling for children to show reverence to their parents. And she concludes by picturing him as responsible for her 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 not to understand that if he leads the Volscians away from Rome, it will mean his death. After Coriolanus gives in and points out to Volumnia the implications of his concession to her, she is silent. When the women return to Rome, they are greeted by a tumultuous welcome. Volumnia does not respond to the senator who congratulates her on her achievement.