He is most noted for his stand against the sack of Thessalonica by the Normans in 1185, contemporary account of the event, for his orations and for his commentaries on Homer, which incorporate many remarks by much earlier researchers.

[1] A pupil of Nicholas Kataphloron, Eustathius was appointed to the offices of superintendent of petitions (ἐπὶ τῶν δεήσεων, epi ton deeseon), professor of rhetoric (μαΐστωρ ῥητόρων), and was ordained a deacon in Constantinople.

[citation needed] Accounts of his life and work are given in the funeral orations by Euthymius and Michael Choniates (of which manuscripts survive in the Bodleian Library in the University of Oxford).

He wrote commentaries on ancient Greek poets, theological treatises, addresses, letters, and an important account of the sack of Thessalonica by William II of Sicily in 1185.

Of his works, his commentaries on Homer are the most widely referred to: they display an extensive knowledge of Greek literature from the earliest to the latest times.