Plarianus came from a prominent family of Ostia, known from numerous inscriptions recovered from that port city of Rome.
His father was Aulus Egrilius Rufus, a prominent decurion of Ostia, attested as duovir and flamen Romae et Augusti; his mother was Plaria Q.f.
[2] Through his mother's family, the Plarii, Plarianus could trace a connection with the Senatorial Acilii Glabriones: Manius Acilius Glabrio, consul in 91, had married Arria L.f. Plaria Vera Priscilla, another member of the Plarii.
Plarianus is attested as having been prefectus of the aerarium Saturni from the year 123 to 125, when his brother succeeded him in that role.
Although the name of his wife has not yet been discovered, Plarianus is known to have had one son, also named Aulus Egrilius Plarianus, who was prefectus of the aerarium militare, but did not advance to the consulate for unknown reasons.