Metis personifies a quality that joins wisdom to practical cunning. By the Classical period philosophers and Stoic allegory treated her as prudence or wise counsel; earlier the name also suggested the trickster cleverness associated with figures such as Prometheus.

Hesiod counts her among the three thousand Oceanids. She is not to be confused with later philosophical abstractions that borrow her name, nor with unrelated modern uses (asteroid, Jovian moon) that commemorate her.

In the succession myth Metis gives Zeus an emetic that forces Cronus to disgorge the swallowed Olympians — Hestia, Demeter, Hera, Hades, and Poseidon — clearing the way for the Titanomachy. After the Olympians' victory Zeus marries her as his first consort.

Apollodorus instead tells a pursuit in which Metis changes shapes to escape Zeus before he overpowers her. A scholiast likewise credits her with shape-changing; Zeus swallows her after tricking her into a smaller form (often restored as a fly).

Gaia and Uranus warn that Metis will bear first a daughter wiser than herself and then a son who would be king of gods and men. To forestall the son, Zeus swallows Metis while she is already pregnant with Athena. Hesiod says she remains within him, wiser than gods and mortals, and continues to counsel him from inside.

Athena later emerges fully armed from Zeus's head — often with Hephaestus (or another helper) splitting the skull. Some accounts have Metis forge the child's armour within Zeus. An alternative tradition makes the Cyclops Brontes Athena's father before the swallowing. Plato makes Poros ("resource") a son of Metis.