He was distinguished by his contemporaries for the excellence of his character and his cultivation of philosophy and the liberal arts and is considered by some historians to have been the greatest of the kings of Cappadocia.

Rather, Ariarathes Eusebes probably spent his youth studying in Athens, where he seems to have become a friend of the future king of Pergamon, Attalus II Philadelphus.

In consequence of rejecting, at the wish of the Romans, a marriage with Laodice V, the sister of Demetrius I Soter, the latter made war upon Ariarathes, and brought forward Orophernes of Cappadocia, his brother and one of the supposed sons of the late king, as a claimant of the throne.

He was restored to his throne by the Romans, who, however, allowed Orophernes to reign jointly with him, as is expressly stated by Appian,[6] and implied by Polybius.

After she had been put to death by the people on account of her cruelty, her only surviving son succeeded to the crown as Ariarathes VI of Cappadocia.