Agoracritus came from the island of Paros and worked in the later fifth century BCE. His precise birth date and arrival in Athens are not securely established. Ancient writers connect him closely with Phidias, the sculptor associated with the Athenian building programme and the great images of Athena and Zeus. Pliny describes Agoracritus as a favoured pupil and reports that Phidias allowed the younger artist to receive credit for some of his own works. The anecdote shows how closely their reputations became intertwined, although it cannot establish the authorship of every disputed statue.

Agoracritus has also been associated with sculpture on the Parthenon. In his reconstruction of the Nemesis from Rhamnous, George Despinis identified stylistic characteristics that he used to propose a role for Agoracritus and his workshop in parts of the Parthenon's friezes and pediments. The treatment of drapery was especially important: folds could suggest the form of the body beneath the clothing while retaining their own elaborate movement. These connections are scholarly attributions based on comparison, not signatures preserved on the Parthenon figures. They help explain how researchers try to distinguish individual artists within a large workshop tradition.

The best-known rivalry comes from Pliny. He reports that Agoracritus and Alcamenes, both pupils of Phidias, competed to make an image of Aphrodite. According to this account, the Athenians favoured Alcamenes because he was their fellow citizen, rather than because his work was better. Pliny says that Agoracritus sold his statue on condition that it should not remain in Athens and called it Nemesis; it was set up at Rhamnous in Attica. The story offers an explanation for the statue's identity and location, but it is an anecdote rather than a securely documented competition. It does not establish exactly what physical alterations, if any, were made to the figure.

Pausanias preserves a different story about the marble. He says that the Persians brought a block to Marathon intending to make a trophy after their expected victory, only for their defeat to turn it into material for an image of Nemesis. In his account the sculptor is Phidias, not Agoracritus. The tale makes the goddess of retribution answer an army's premature confidence. It should therefore be presented as an ancient explanation of the monument, not as verified evidence for the stone's transport or the statue's commission. The competing attribution also matters: ancient accounts did not agree on every part of the work's history.

The statue itself was a monumental standing figure, reconstructed at approximately three and a half metres high. Pausanias describes a crown decorated with deer and small figures of Victory, an apple branch in one hand and a cup in the other. The base showed Helen being brought to Nemesis by Leda, together with other figures connected with the story. This followed the tradition in which Nemesis was Helen's mother and Leda her nurse. A damaged head and numerous marble fragments preserve physical evidence for the image, while ancient descriptions and later copies help explain its appearance. Agoracritus was also associated with an image of the Mother of the Gods and with statues of Athena Itonia and Zeus at Koroneia.

The Nemesis eventually survived only in fragments. Its destruction has been discussed in relation to late-antique religious change, but a precise event and its perpetrators should not be presented as settled facts. Excavation at Rhamnous in 1812-1813 recovered the head now catalogued by the British Museum. In the late 1960s and early 1970s, Despinis studied and assembled hundreds of further fragments, allowing a much fuller reconstruction of the statue and its style. Agoracritus's surviving reputation thus rests on several kinds of evidence: the stone itself, the ancient stories attached to it and the modern work of identifying what the fragments once formed.