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 he recites in the Symposium is full of the sort of artificial rhetorical expressions which might be expected from a former pupil of Gorgias. Aristotle tells us that he was the first to introduce into the drama arbitrary choral songs, unrelated to the subject, and that he wrote pieces with fictitious names which appear to have been halfway between the idyl and comedy. His intimacy with Aristophanes doubtless saved him from many well-deserved strictures, though in the Thesmophoriazusae the comic poet burlesques his flowery style and represents him as a delicate and effeminate youth; it may be only for the sake of punning on his name (Áγαθός = "good") that he makes Dionysus call him a noble poet.
Agathon was also a friend of Euripides, another recruit to the court of Archelaus of Macedon. He seems, however, to have had all the faults, and little of the genius, of his famous contemporary. He tended to excess, attempting to surprise his spectators with unexpected developments and strange, improbable dénouements. Add to this his fondness for epigram, antithesis and other rhetorical embellishments, after the fashion of Gorgias, and it's no wonder that whatever he possessed of ability was smothered beneath his mannerisms. All the same, he appears to have been proud of his quirks, considering them essential to his verse; when asked to purge his work of such blemishes, he replied, "You do not see that that would be to purge Agathon's play of Agathon." His poetry was full of tropes, inflection and metaphor; it had the glitter of sparkling ideas flowing smoothly along, with harmonious diction and deft construction, but it lacked real vigor of thought and expression. With him begins the decline of tragic art in its higher sense.
Agathon's extraordinary physical beauty is brought up repeatedly in the sources; the historian W. Rhys Roberts observes that "ὁ καλός Ἀγάθων has become almost a stereotyped phrase. Our most detailed description of Agathon can be found in Aristophanes' comedy, the Thesmophoriazousae, in which Agathon appears as a pale, cleanshaven young man, dressed in women's clothes. Regrettably, it is hard to determine how much of Aristophanes' portrayal is fact and how much mere comic invention.
After a close reading of the Thesmophoriazousae, the historian Jane McIntosh Snyder observed that Agathon's costume was almost identical to that of the famous lyric poet Anacreon, as he is portrayed in early 5th-century vase-paintings. Snyder theorizes that Agathon might have made a deliberate effort to mimic the sumptuous attire of his famous fellow-poet, although by Agathon's time, such clothing, especially the κεκρύφαλος (an elaborate covering for the hair) had long fallen out of fashion for men. According to this interpretation, Agathon is mocked in the Thesmophoriazousae not only for his notorious effeminacy, but also for the pretentiousness of his dress: "he seems to think of himself, in all his elegant finery, as a rival to the old Ionian poets, perhaps even to Anacreon himself.
Agathon has been thought to be the subject of Lovers' Lips, attributed to the philosopher Plato:
A looser translation reads:
Although the authenticity of this epigram was accepted for many centuries, it was probably not composed for Agathon the tragedian; nor was it composed by Plato. Stylistic evidence suggests that the poem (with most of Plato's other alleged epigrams) was actually written some time after Plato had died: for its form is that of the Hellenistic erotic epigram, which did not become popular until after 300 B.C. According to 20th-century scholar Walther Ludwig, the poems were spuriously inserted into an early biography of Plato--sometime between 250 B.C. and 100 B.C.--and adopted by later writers from this source.