After holding the senior offices in the province of Aegyptus (Egypt), he went to Rome c. 120, where he practiced as an advocate, pleading cases before the emperors (probably as advocatus fisci, an important official of the imperial treasury).

[1] It was in 147 at the earliest that he was appointed to the office of procurator, probably in Egypt, on the recommendation of his friend Marcus Cornelius Fronto, an influential rhetorician and advocate.

Because the position of procurator was open only to members of the equestrian order (the "knightly" class), his possession of this office tells us about Appian's family background.

His principal surviving work (Ρωμαϊκά Romaiká, known in Latin as Historia Romana and in English as Roman History) was written in Greek in 24 books, before 165.

It gives an account of various peoples and countries from the earliest times down to their incorporation into the Roman Empire, and survives in complete books and considerable fragments.

Since his parents were Roman citizens capable of paying for their son's education, it can be inferred that Appian belonged to the wealthy upper classes.

The emperors he claims to have addressed must have been either Hadrian or Marcus Aurelius and definitely Antoninus Pius, for Appian remained in Egypt at least until the end of the reign of Trajan (117).

In the letter of Cornelius Fronto, it is revealed that a request on behalf of Appian to receive the rank of procurator occurred during the co-regency of Marcus Aurelius and his brother Lucius Verus between 147 and 161.

These five books stand out because they are one of the few comprehensive histories available on the transition of the Roman state from Republic to Empire and the ensuing civil and military strife.

He may have relied primarily on one author for each book, whom he did not follow uncritically, since Appian also used additional sources for precision and correction.