Ariobarzanes was the son of a Persian nobleman named Pharnabazus II, who was satrap of Hellespontine Phrygia, i.e., the northwest of what is now Turkey. The family belonged to the highest Persian elite: its founder was another Pharnaces I, who had in the late sixth century been mayor of the palace of his nephew, king Darius I the Great. The descendants of this Pharnaces remained closely related to the great king: for example, Ariobarzanes' father was married to a daughter of king Artaxerxes II Mnemon, Apame. (She was not Pharnabazus' first wife and not Ariobarzanes' mother.)
In 407, Ariobarzanes served as envoy. He had to bring back several Athenian ambassadors, who had been staying at the satrapal court of his father at Dascylium, to the coast, from where they could return to Athens. It seems that in these days, Ariobarzanes also became friends with Antalcidas, a Spartan nobleman.
His father Pharnabazus II played an important role during the Corinthian War between Sparta and the other Greek towns (395-387). He supported Sparta, which had to pay for the Persian help: it had to sacrifice the Greek cities in Asia, which became subjects of the great king. Pharnabazus was rewarded with another, more important office, and Ariobarzanes succeeded him (387).
The new satrap had good connections with Athens and Sparta, and when he decided to revolt (for unknown reasons) against king Artaxerxes II Mnemon in his twentieth year in office, he received support from both Greek towns. For example, the Spartan king Agesilaus came to Asia with a mercenary force. Several other satraps sided with Ariobarzanes: Maussolus of Caria (briefly), Orontes of Armenia, Autophradates of Lydia and Datames of Cappadocia. The rebel satraps also received support from the pharaoh of Egypt, Teos. Ariobarzanes spent some time in Assos, where he was besieged by the Persians, but with so much support and an enemy so divided, he held out.
In return for the support from Athens, Ariobarzanes presented the Greek city with Sestos, a town at the entrance of the Hellespont that had once been Athenian. The grateful Athenians made him citizen of their city.
In the winter of 363/362, the rebels were defeated; Ariobarzanes was betrayed by his son Mithradates and was crucified. He was succeeded by his half-brother Artabazus II.