Medea is a foreign-born princess from Colchis and a powerful witch currently residing in Corinth as a political exile. Having abandoned her homeland to assist Jason in securing the Golden Fleece, she finds herself dangerously isolated after he abruptly divorces her. She experiences profound grief and burning anger over her vulnerable social standing. She is fiercely clever and highly sensitive to mockery, refusing to quietly accept the systemic disadvantages forced upon women in Greek society.

Jason is a famous Greek hero and the former captain of the Argo, currently living as a refugee in Corinth. Seeking to escape his degraded status and secure powerful allies, he divorces Medea to marry the local Corinthian princess. He views his actions as practical and socially acceptable, failing to understand Medea's expectation to be treated as a martial equal rather than a subordinate wife.

Creon is the king of Corinth and Jason's new father-in-law. Relying heavily on gossip and reputation, he views Medea as a dangerous foreign threat to his family and his city. Though he attempts to act ruthlessly by demanding her immediate exile, his fear of appearing tyrannical makes him susceptible to her manipulation.

Aegeus is the king of Athens who visits Corinth after consulting an oracle regarding his inability to father an heir. He is good-natured and respects Medea's intellect, actively seeking her advice to interpret the oracle's prophecy. He sympathizes with her plight and values their friendship over the political complications it might cause with Corinth's rulers.

The Chorus consists of native freeborn Corinthian women who live near Medea. They possess the security of ancestral homes and established alliances that Medea lacks, but they relate to her grievances regarding the poor treatment of wives. They function as a sounding board for Medea and represent the societal conscience of the community.

The Nurse is an elderly enslaved woman who has cared for Medea since her childhood in Colchis. She possesses an intimate understanding of her mistress's volatile nature and deep depression. Recognizing the danger brewing within Medea's mind, she acts protectively toward the household while fearing specifically for the safety of the children.

The Tutor is an enslaved man responsible for the education and daily care of Jason and Medea's children. He is pragmatic about the behavior of men in Greek society, viewing Jason's abandonment of his family as a common occurrence rather than an exceptional betrayal.

The two young boys are the children of Jason and Medea. They are innocent bystanders in the fierce domestic dispute between their parents, caught directly between Jason's desire for an extended royal family and Medea's intense rage.

The unnamed royal daughter of King Creon. Her marriage to Jason grants him a secure place in Corinthian society while precipitating Medea's disastrous exile. She remains an unseen presence for most of the story, representing the social legitimacy and safety that Medea has lost.

Aietes is the king of Colchis and Medea's father. He possessed the Golden Fleece until Medea betrayed him to help Jason steal it, permanently severing her ties to her homeland.

Helios is the Greek god of the sun and Medea's divine grandfather. He represents Medea's powerful, otherworldly lineage, which operates outside the standard bounds of mortal justice or Corinthian law.