"It is not possible either to trick, escape, or defeat the mind of Zeus."
Cronos, his father, had sired six children with Rhea, his wife: Poseidon, Hades, Demeter, Hestia, Hera, and Zeus himself. But Cronos swallowed them all because of a prophecy claiming that he would be overthrown by his son, as he had overthrown his own father. Rhea, seeking revenge, hid Zeus at birth and gave Cronus a rock wrapped in cloth to swallow instead.
After reaching manhood, Zeus forced Cronus to disgorge first the stone then his siblings in reverse order of swallowing. In some versions, Metis gave Cronus an emetic to force him to disgorge the babies, or Zeus cut Cronus's stomach open. Then Zeus released the brothers of Cronus, the Gigantes, the Hecatonchires and the Cyclopes, from their dungeon in Tartarus, killing their guard, Campe.
As a token of their appreciation, the Cyclopes gave him thunder and the thunderbolt, or lightning, which had previously been hidden by Gaia. Together, Zeus and his brothers and sisters, along with the Gigantes, Hecatonchires and Cyclopes overthrew Cronus and the other Titans, in the combat called the Titanomachy. The defeated Titans were then cast into a shadowy underworld region known as Tartarus. Atlas, one of the titans that fought against Zeus, was punished by having to hold up the sky.
After the battle with the Titans, Zeus shared the world with his elder brothers, Poseidon and Hades, by drawing lots: Zeus got the sky and air, Poseidon the waters, and Hades the world of the dead (the underworld). The ancient Earth, Gaia, could not be claimed; she was left to all three, each according to their capabilities, which explains why Poseidon was the "earth-shaker" (the god of earthquakes) and Hades claimed the humans that died. Gaia resented the way Zeus had treated the Titans, because they were her children. Soon after taking the throne as king of the gods, Zeus had to fight some of Gaia's other children, the monsters Typhon and Echidna. He vanquished Typhon and trapped him under Mount Etna, but left Echidna and her children alive.
Zeus was infamous for his lust of mortals, indeed the king of the gods transcended male or female and even species when it came to his many affairs. His lascivious actions in bed always left a very positive mark on the mortals he slept with which enraged Hera to no end. Zeus was known to have slept with many women aside from Hera, and he had many sons and daughters. The most well known of them are Aphrodite, Hermes, Ares, Apollo, Artemis, Athena, Hephaestus, Dionysus and Hercules.
Zeus was also the upholder of the universal order. He gave justice to mortals to help civilize them and was in charge of punishing oath-breakers, liars, and violators of sacred hospitality. The ancient Greek interpretation of the world was very different from modern values with gods being held as the center of the universe instead of mortals. Zeus enforced a harsh sense of justice upon humans to keep them in line. Though he usually allowed his fellow gods to do whatever they wanted to mortals he would sometimes intervene to mitigate the damage they caused when they went too far.