Atlas was the son of the Titan Iapetos and the Oceanid Clymene. Atlas had three brothers — Prometheus, Epimetheus and Menoetius. With different goddesses he was the father of the Hesperides sisters, Maera, Hyas, the Hyades sisters, Kalypso and the Pleiades sisters. A late mythographer, Hyginus, (Fabulae 82, 83) says that Dione was also a daughter of Atlas.
Atlas led the Titans in one of their wars against the Olympians. His brothers Prometheus, Epimetheus and Menoitios weighed the odds and betrayed the other Titans by an alliance with the Olympians. When the Titans were defeated, Zeus condemned Atlas to stand at the western edge of the earth and hold up the heavens on his shoulders, to prevent the two from resuming their primordial embrace.
In a late story, a giant named Atlas tried to drive a wandering Perseus from the place where the Atlas mountains now stand. Perseus revealed Medusa's head, turning Atlas to stone. As is not uncommon in myth, this account cannot be reconciled with the far more common stories of Atlas' dealings with Heracles, who was Perseus' great-grandson.
Encounter with Herakles
One of the hero Heracles' Twelve Labors involved the acquisition of some of the golden apples which grow in Hera's garden, tended by the Hesperides and guarded by the dragon Ladon. Herakles went to Atlas, the father of the Hesperides, and offered to hold the heavens for a little while in exchange for the apples, to which Atlas agreed. Upon his return with the apples, however, Atlas attempted to trick Herakles into carrying the sky permanently by offering to deliver the apples himself. Herakles, suspecting Atlas didn't intend to return again, pretended to agree to Atlas' offer, asking only that Atlas take the sky again for a few minutes so Herakles could rearrange his cloak as padding on his shoulders. When Atlas set down the apples and took the heavens upon his shoulders again, Herakles took the apples and went on his way.
The etymology of the name Atlas is uncertain and still debated. Some derive it from the Proto-Indo-European root *tel, 'to uphold, support'; others suggest that it is a pre-Indo-European name. Since the Atlas mountains fell in the region inhabited by Berbers, it could be that the name as we know it is taken from Berber.