Agathon was the lifelong companion of Pausanias, with whom he appears in both the Symposium and Plato's Protagoras. Together with Pausanias, he later moved to the court of Archelaus, king of Macedon,
who was recruiting playwrights; it is here that he probably died around
401 BC. Agathon introduced certain innovations into the Greek theater: Aristotle tells us in the Poetics that the characters and plot of his Anthos were original and not, following Athenian dramatic orthodoxy, borrowed from mythological subjects. Agathon was also the first playwright to write choral parts which were apparently independent from the main plot of his plays.
Agathon is portrayed by Plato as a handsome young man, well dressed,
of polished manners, courted by the fashion, wealth and wisdom of
Athens, and dispensing hospitality with ease and refinement. The epideictic speech in praise of love which Agathon recites in the Symposium is full of beautiful but artificial rhetorical expressions, and has led some scholars to believe he may have been a student of Gorgias. In the Symposium,
Agathon is presented as the friend of the comic poet Aristophanes, but
this alleged friendship did not prevent Aristophanes from harshly
criticizing Agathon in at least two of his comic plays: the Thesmophoriazousae and the (now lost) Gerytades. In the later play Frogs,
Aristophanes softens his criticisms, but even so it may be only for the
sake of punning on Agathon's name (ἁγαθός = "good") that he makes
Dionysus call him a "good poet".
Agathon was also a friend of Euripides, another recruit to the court of Archelaus of Macedon.