Son of Peleus (a mortal), and Thetis (a sea nymph), Achilles' mother was given a choice by the gods (Greek) as to how his life should be: short but glorious or long but obscure. Fearing for her son's safety, Thetis chose the latter, and to this end bargained with the gods to protect her son from harm. This they granted, by advising the nymph to immerse the child in the waters of the Styx, which would immunize him from all harm. This Achilles' mother did, but having to hold on to her son by the ankle, that he would not be dragged away by the current, this part of the boy did not receive the protection of the gods, and indeed was to prove the death of Achilles.

Fearing further for the boy's safety, Thetis disguised Achilles as a girl and sent him to the court of King Lykomedes on the island of Skyros. There he was brought up as a girl, among the king's daughters, falling in love with one of them, Deidamia, who bore him a son, Neoptolemos, who later fought in the war against Troy. However, another Greek hero, Odysseus, was sent to Skyros, his mission to locate Achilles and enlist him in the coming Trojan War. Gaining admittance to the court of King Lykomedes under a false pretext, Odysseus recognized Achilles, and ordered a magnificent suit of armour to be brought before the boy. Seeing the breathtaking splendor of the suit, Achilles' head was turned, and he yielded to the call to arms that Odysseus sounded on his battle-horn. The boy offered his services to the war, and was enlisted, as had been Odysseus' intention in the first place.

On the way to Troy, the Greek party mistakenly landed in Mysia, which was ruled by Telephos, a son of Hercules. Telephos fought the invasion of his country, and in the battle was wounded by Achilles' spear. Achilles had studied healing and medicine under the Centaur Cheiron, and this knowledge had stood him in good stead when he had had to heal a wound that his friend Patroklos suffered. Telephos found that his wound would not heal, and on consulting an oracle, was advised that it would only be healed by he who had caused it. With the Greek fleet beached at Aulis, Telephos made his way there, where he presented himself to King Agamemnon, in disguise. He then abducted Agamemnon's infant son, Orestes,and threatened to kill the child if his wound were not seen to. Thereupon Odysseus scraped some of the rust from the spear of Achilles, applied it to the wound, which then healed. Delighted with the results, Telephos offered to lead the Greeks to Troy, which was in fulfillment of another oracle.

Achilles then went on to distinguish himself in the long and hard-fought Trojan War, leading the Greeks to the brink of victory, and fulfilling the fate laid out for him by the gods, his mother's choice of which he had himself superseded, once having given in to the call of the warrior, there in Lykomedes' court. In the course of the Trojan War, Achilles gained great fame and respect, killing the Hero of Troy, Hector, as well as the Amazon Pentheselia, before finally being killed himself by Paris, instigator of the Trojan War by his stealing of the beautiful Helen from her husband Menalaus. Paris killed Achilles by means of a poisoned arrow, which by chance hit him in his unprotected heel.