By the eighth century BC, an aristocratic clan called the Bacchiadae ran Corinth, perhaps a couple hundred adult males who took power from the last king Telestes around 747 BC and ruled by annually electing a single magistrate. Under them, Corinth became the most advanced city in Greece and founded major colonies at Corcyra in 733 BC and Syracuse the same year. Then came the prophecy. Herodotus reports that the Bacchiadae heard from the Delphic oracle that the son of a man named Eëtion would overthrow their dynasty. Eëtion's wife Labda gave birth to a baby named Cypselus, and the men sent to kill the infant could not bring themselves to do it; the baby smiled at each of them. Labda hid him in a chest. Cypselus grew up, used his position as polemarch to expel the Bacchiadae in 657 BC, and ruled Corinth as tyrant for thirty years. He needed no bodyguard. He died of old age.

Cypselus's son Periander succeeded him in 627 BC and ruled for forty years. He was counted among the Seven Wise Men of Greece, struck the city's first coins, and tried to dig a canal through the Isthmus to connect the Aegean and the Ionian Sea. He gave up. The technology of the sixth century BC could not move that much rock. Instead he built the Diolkos, a paved overland ramp where ships could be hauled across the Isthmus on rollers, charging tolls for the service. The Diolkos worked. Some of the limestone paving still survives. Periander's reign was prosperous, but personally tragic. He killed his wife Melissa in a rage. His son Lycophron, learning what had happened, refused to speak to his father and was exiled to Corcyra. When Periander tried to bring him home, the Corcyreans, terrified of having Periander rule them, killed Lycophron instead.

In the classical period, Corinth's rivalry with Athens and Thebes was the rivalry of equals. Until the mid-sixth century BC, Corinth dominated the Greek pottery trade with its black-figure ceramics. Corinthian architects gave the world the third order of classical architecture, the elaborate Corinthian column with its acanthus-leaf capital, while the Doric expressed Spartan severity and the Ionic an Athenian middle path. Thucydides credits the Corinthians with the trireme, the three-banked warship that became the standard naval vessel of the Mediterranean for nearly a thousand years. During the Persian Wars, Corinth contributed 400 hoplites to defend Thermopylae and 40 warships at Salamis under the admiral Adeimantos. At Plataea, 5,000 Corinthian hoplites fought in their distinctive helmets. Herodotus, who is generally said to have disliked the city, conceded that the Corinthians were considered the second-best fighters of all the Greeks, after the Athenians.

In 146 BC, after a long political dispute over the Achaean League, Rome sent the consul Lucius Mummius against Corinth. The army sacked the city, killed many of its men, sold the women and children into slavery, and demolished the buildings. The empty site sat almost vacant for a century. In 44 BC, just before his assassination, Julius Caesar refounded Corinth as a Roman colony, and the city quickly became the provincial capital of Achaea. The new Corinth filled with Roman citizens, freed people, and Greek-speaking immigrants from the eastern Mediterranean. Around AD 50, Paul the Apostle arrived, stayed eighteen months, and wrote letters back to the community he had founded that became the First and Second Epistles to the Corinthians. Systematic excavations of the site have continued under the American School of Classical Studies at Athens since 1896. The seven standing columns of the Temple of Apollo, built around 540 BC, survived both the Roman destruction and most of what came after.