He followed a military career: between 441 and 443 he is attested as dux or magister utriusque militiae. In 441 he was in Tarraconensis (Spain), where he defeated the Bagaudae. In 443 he was succeeded by his son-in-law Merobaudes.
He was appointed consul for the year 449. At the beginning of his office he was in Gaul (probably in the capital city of the praetorian prefecture, Arelate), and Nicetius delivered a panegyric in his honour.
A consular diptych produced by Astyrius in 449 is preserved at Liège. The diptych shows Astyrius seated on a curule chair wearing complete consular regalia and the inscription Flavius Astyrius vir clarissimus et inlustris comes ex magistro utriusque militiae consul ordinarius.
- As spelled on his consular diptych (CIL XIII, 10032.2).
- As shown by the vir clarissimus rank.
- Hydatius, 125 (sub anno 441).
- Hydatius, 128 (sub anno 443).
- Sidonius Apollinaris, Epistulae III.6.5.
- The vir clarissimus rank was bestowed to aristocracy members since their birth.
- The vir inlustris rank was awarded by the Emperor to a few high officers, among whom the magister utriusque militiae.
- The rank of comes was probably conferred to Astyrius at the end of his office as magister utriusque militiae.
- "Fl. Astyrius", Prosopography of the Later Roman Empire, Volume 2, pp. 174-175.
- Ralph W. Mathisen, People, Personal Expression, and Social Relations in Late Antiquity, University of Michigan Press, 2003, ISBN 0-472-11246-5, pp. 18-19.
Fl. Rufius Praetextatus Postumianus,
| Consul of the Roman Empire
with Fl. Florentius Romanus Protogenes
Imp. Caes. Fl. Placidus Valentinianus Augustus VII,