Along with his brother Telamon, they accidentally killed their half-brother, Phocus, while hunting, and were forced to flee the island of Aegina, in order to avoid punishment. When they reached the region of Phthia, Peleus fell in love with Antigone, the daughter of the region's king Eurytion, with whom he had a daughter, Polydora. Peleus, Telamon, and Eurytion were all participants in the Argonautic Expedition, in Jason's quest to retrieve the Golden Fleece. Some time later, yet in another hunting accident, Peleus killed Eurytion and had to flee.
Peleus reached Iolcus, where the king's wife, Astydameia, fell in love with him. Peleus denied her advances, and for revenge, Astydameia sent a message to Antigone, saying that Peleus would marry her daughter. Antigone was so bitter that she hanged herself. Astydameia then falsely accused Peleus of trying to rape her; the king, Acastus, took Peleus into a forest where he abandoned him just before an attack by centaurs. Peleus was saved by Chiron, a wise centaur, or Hermes, the messenger god. Peleus escaped, ransacked Iolcus, and killed both Astydameia and Acastus.
Later, Peleus met Thetis, a sea nymph who was able to change form. Aided by Proteus, Peleus managed to win her heart. Their marriage was a grand event that was attended by most Olympian gods. However, the goddess of strife, Eris, was not invited; angry that she was scorned, Eris dropped the Apple of Discord among the guests, a golden apple that had an inscription reading "To the fairest". Hera, Athena, and Aphrodite started arguing over who should be the one to receive the apple, and told Zeus to decide. Zeus, reluctant to give an answer, said that the best person to decide was Paris, prince of Troy, who was also attending the wedding. After being bribed by the goddesses, Paris eventually picked Aphrodite, who had promised him she would give him the most beautiful woman in the world, Helen. This was the event that eventually culminated in the Trojan War.
Peleus and Thetis had seven sons, but the six of them died when they were born. Only one son survived, who was named Achilles. Thetis decided to make Achilles invulnerable by dipping him in the River Styx; however, she did not realise that his heel, the part from which she was holding him, was not touched by the river waters, and was thus left vulnerable. This later became Achilles' doom, as a poisonous arrow shot by Paris and guided by Apollo during the Trojan War hit him in his heel and killed him.