Eutropius was born in one of the Roman provinces of the middle east, either Assyria or on the border of Armenia. According to Honorius' court poet Claudian, who composed a satirical invective against Eutropius due to the latter's hostility to Claudian's patron, Stilicho, Eutropius served successively as a catamite, pimp, and body-servant to various Roman soldiers and nobles, before winding up among the domestic eunuchs of the imperial palace. After Theodosius' death in 395 he stood at the head of a faction opposed to the powerful Praetorian Prefect of the east, Rufinus, and successfully arranged the marriage of the new emperor, Arcadius, to Aelia Eudoxia, the daughter of general Bauto having blocked an attempt by Arcadius' chief minister to increase his power by marrying the young and weak-willed emperor to his daughter. After Rufinus' assassination that same year, Eutropius rose in importance in the imperial court, and he soon became Arcadius' closest advisor. He also played a role in the Gildonic War by encouraging Gildo's revolt against Stilicho's machinations. Eutropius' ascension to power was assisted by his defeat of a Hun invasion in 398. The next year he became the first eunuch to be appointed a consul.
During his rise to the consulship, Eutropius earned a notoriety for cruelty and greed. He may also have played a role in the assassination of his predecessor Rufinus. In 399, the year of his consulship, he sent Gaïnas, the magister militum at the time, to quell Tribigild's rebellion. However, Gainas and Tribigild teamed up to persuade Arcadius to dismiss Eutropius. In the meantime, Eutropius had also been estranged from Eudoxia, the very empress he had installed, who appeared to her husband wailing with her infant daughters about the eunuch's alleged schemes against her. Moved by his subordinates' threats and compassion for his family, Arcadius exiled Eutropius.
After Eutropius's fall from power, his ally John Chrysostom's pleas kept him alive for a short time; he was eventually executed before the year ended. A surviving imperial edict shows that he was subjected to damnatio memoriae and his property was confiscated.