In 392 BC, while the Corinthian War was being contested amongst the Greek states, Tiribazus received envoys from the major belligerents of that war, and held a conference in which a proposal for ending the war was discussed. That discussion failed, but Tiribazus, convinced that Athens was becoming a threat to Persia in the Aegean, secretly provided funds to rebuild the Spartan fleet. When the Persian king Artaxerxes II learned of this, Tiribazus was removed from power and replaced by Struthas, who pursued an anti-Spartan policy.
However, five years later, in 387 BC, Tiribazus was again in power, and worked together with the Spartan general Antalcidas to rebuild the Spartan fleet as a threat to Athenian interests in the region. This action brought the Athenians and their allies to the negotiating table. Tiribazus represented Artaxerxes at the ensuing negotiations, which led to the Peace of Antalcidas.
In 386/385 BC, Tiribazus was made joint commander of the Persian expedition against Evagoras I (r. 411–374 BC), the king of Salamis in Cyprus. He was assigned to the lead the Persian navy, while Orontes I, the satrap of Armenia, led the land forces. Tiribazus reportedly knew Orontes from his early days in Armenia, where he had served as the hyparch of its western part till 395 BC. By 382 BC, preparations for the campaign had been made, with a battle taking place the following year near the Cyprian city of Kition, where the Persians emerged victorious due to their larger fleet. Evagoras withdrew to Salamis, which he started fortifying.
Failing to gain help from the Egyptian pharaoh Hakor (r. 392/1–379/8 BC), Evagoras started to negotiate a peace treaty with Tiribazus, offering to withdraw from all the cities of Cyprus except Salamis, and pay a fixed yearly tribute to the Persian crown. Tiribazus was inclined to accept the offer, but the negotiations failed after Evagoras refused to also cede his status as king. The negotiations between Evagoras and Tiribazus led to Orontes to send a number of accusations to Artaxerxes II, which mentioned that Tiribazus was deliberately prolonging the war and planning to declare independence. Artaxerxes II was unable to make a proper assessment due to his distance, but could not risk Tiribazus ruin the recent Persian accomplishments, and as a result had him jailed in Susa, heavily weakening the position of the Persian expedition.
Glos, who was the father-in-law of Tiribazus, fearing for his own position, started plotting against Artaxerxes II and secretly making peace with Egypt and Sparta. Evagoras started to help from the Spartans and gave Glos information that would jeopardize Orontes' position. Under the threat of blackmail, Orontes was forced to make peace with Evagoras in 380 BC. The terms of the treaty was that Evagoras was obligated to pay tribute to the Persian king, but as a subordinate king rather than a slave. Artaxerxes III did not deem the conclusion of the war satisfactory, as it had cost 15,000 talents, and a result Orontes fell into disfavour. Meanwhile, Tiribazus was pardoned and restored to his former position.
Tiribazus now stood higher than ever in the royal favour, and received a promise of the hand of Amestris, the king's daughter. Artaxerxes, however, reneged on this arrangement, and married Amestris himself.
When King Artaxerxes reneged on a pledge to Tiribazus once more, this time with respect to Atossa, the youngest of the king's princesses, Tiribazus could no longer remain loyal to the king and incited Darius, the son of Artaxerxes, to join him in a plot against the king's life.
Tiribazus' plans were betrayed to Artaxerxes by a eunuch, and the conspirators were found out. Tiribazus offered a desperate resistance to the guards who endeavored to arrest him, and was slain with a javelin.