Hecuba was born into royalty, the daughter of Dymas, the king of Phrygia, or in some accounts of Cisseus, the king of Thrace. She married Priam, the king of Troy, and became the queen of the wealthiest city in Asia Minor, a fortress whose walls were said to have been built by Poseidon, the god of the sea, and Apollo, the god of light. She bore Priam many children, some say nineteen in all, the most famous being Hector, the heir to the Trojan throne and the bulwark of the city's defence; Paris, the prince whose judgment of the three goddesses and subsequent abduction of Helen, the most beautiful woman in Greece, brought the Achaean fleet to Troy's shores; Cassandra, the priestess of Apollo whose beauty attracted the god himself, and who was cursed with the gift of true prophecy that no one would ever believe; and the two youngest, Polyxena, a maiden of marriageable age, and Polydorus, a boy too young to fight.

The war that Paris started lasted ten years, and Hecuba watched it from the walls of Troy, from the heights of the citadel called Pergamos. She saw her son Hector duel Achilles, the greatest warrior of the Greeks, and she saw Hector dragged dead behind Achilles's chariot around the walls of the city she had ruled. She saw her daughter Cassandra dragged from the temple of Athena by Ajax, the lesser, who raped her at the goddess's altar and escaped punishment because he clung to the goddess's statue. She saw the Greeks build the wooden horse and leave it as a gift, and she heard Cassandra cry out that the horse contained soldiers, and she watched the Trojans disbelieve her, as they always had, and drag the horse inside the gates. When the city fell, Priam was slaughtered at the altar of Zeus by Neoptolemus, the son of Achilles, and Hecuba was taken captive along with the other women of Troy.

The Greeks divided the captive women among themselves as slaves. Hecuba fell to Odysseus, the cunning king of Ithaca whose ten-year journey home would become the subject of Homer's Odyssey. But before she left Troy forever, she had to witness one more death. The ghost of Achilles had appeared above his tomb and demanded the sacrifice of a Trojan princess to ensure favourable winds for the Greek fleet. The Greeks chose Polyxena, Hecuba's daughter, and despite the queen's pleas, the maiden was led to the tomb and killed by Neoptolemus, her throat cut over the grave of the man who had killed her brother. Hecuba collected her daughter's blood in her hands and cursed the Greeks, calling down storms upon their ships, a curse that would scatter the fleet across the Aegean and delay Odysseus's return by ten years.

The worst blow came after the fleet had sailed. Hecuba and the other Trojan women were being held on the Thracian coast when the body of Polydorus washed ashore, stabbed with multiple wounds and pale with death. Hecuba recognised her youngest son and collapsed in grief, for she had entrusted him to Polymestor, the king of Thrace, along with a store of gold to ensure his safety until the war ended. Polymestor had murdered the boy for the treasure and thrown his body into the sea. Hecuba's grief turned to fury, a fury so terrible that the other captive women feared for her sanity. She sent a message to Polymestor saying that she knew where more Trojan gold was hidden and that she would reveal its location only to him, in private, in her tent. Polymestor came, greedy and unsuspecting, and Hecuba's women, the captive Trojan noblewomen who had followed her into slavery, seized him, held him down, and tore out his eyes with their bare hands and brooch-pins. They killed his two young sons before his blinded face, and Hecuba stood over him and exulted in his agony, the queen of Troy avenging her last child with the cruelty of a conqueror.

The accounts of Hecuba's end differ. In Euripides's tragedy, she is still on the Thracian shore when the Greeks prepare to sail, her revenge complete but her life in ruins. In Ovid's Metamorphoses, she is transformed by the gods into a dog, the Cynosura, howling on the shore before she leaps into the sea and drowns, her human voice reduced to a beast's bark. In other traditions, she is buried on the Thracian coast, and her tomb was shown to travellers in antiquity. In every version, she is the victim who refuses to be merely a victim, the queen who takes back her dignity in blood, and the mother whose love outlasts every throne.