Priam was son of Laomedon by Placia, Strymo (or Rhoeo), Zeuxippe or Leucippe in varying accounts. His siblings included Tithonus, Hesione and others. As king of Troy he was said to have fathered fifty sons and many daughters by Hecuba and other wives and concubines — among them Hector, Paris, Helenus, Cassandra, Deiphobus, Troilus, Laodice, Polyxena, Creusa, Polydorus and Polites.

In Iliad Book 3 he tells Helen that he once fought beside King Mygdon of Phrygia against the Amazons. Ancient descriptions call him tall, large and grey, with a pleasant voice; he is traditionally about eighty at Troy's fall.

After Achilles killed Hector and mistreated the corpse, Zeus sent Hermes to escort Priam into the Greek camp. Priam tearfully pleaded for his son's body, invoking Achilles' own father Peleus and saying he had endured what no one on earth had done before — putting his lips to the hands of the man who killed his son. Moved, Achilles returned Hector's corpse and granted a truce for the funeral. The scene closes the Iliad and became one of the most famous episodes of the epic, often depicted in later painting and sculpture.

During the sack Neoptolemus killed Priam. In Virgil's Aeneid Book 2, Neoptolemus first slays Priam's son Polites before his father's eyes as the boy seeks sanctuary at Zeus's altar; Priam rebukes the killer and throws a spear that harmlessly strikes the shield, then is dragged to the altar and slain. Some Greek vase paintings show Neoptolemus clubbing Priam to death with the body of the infant Astyanax.

Priam remains a minor but poignant figure in later opera and drama (Tippett's King Priam, Berlioz's Les Troyens) and in film portrayals from Cedric Hardwicke and John Rhys-Davies to Peter O'Toole in Troy (2004).