Philopappos was a man of aristocratic and well-connected origins. He was the first-born son of the Greek prince of Commagene, Gaius Julius Archelaus Antiochus Epiphanes and an Egyptian Greek woman called Claudia Capitolina. His younger sister and only sibling was the poet and friend to Roman Emperor Hadrian and Roman Empress Vibia Sabina, Julia Balbilla.