Antilochus came from Pylos, the Peloponnesian kingdom ruled by Nestor. His father belonged to an older generation of heroes, and Homer repeatedly presents his experience as a resource for the Greek expedition. Antilochus's mother is named Eurydice or Anaxibia in different accounts. He fought alongside his brother Thrasymedes and was counted among the younger warriors at Troy, but the poems do not require him to be the youngest member of the entire army. His youth matters because it stands beside his father's long experience. Nestor can advise him on judgement, horses and the opportunities of a race; Antilochus must decide what to do when those opportunities arrive. Their relationship gives his later death particular force: the son who receives his father's counsel becomes the man who protects his father's life.

At Troy, Antilochus distinguished himself in loyalty as well as battle. When Hector killed Patroclus, Menelaus sent him to bring the news to Achilles. Antilochus found the hero by the ships and told him that Patroclus was dead and Hector held his armour. Achilles collapsed in grief, covering himself with dust, while Antilochus wept beside him and held his hands, fearing that he might harm himself. This is the encounter that places Antilochus closest to Achilles at a moment of loss. He was not part of the earlier embassy that pleaded with Achilles to return to battle: that mission belonged to Odysseus, Ajax and Phoenix. The Odyssey later says that Achilles valued Antilochus above his other companions after Patroclus, but this does not mean that he instantly replaced Patroclus in every part of the hero's life.

The chariot race at Patroclus's funeral games reveals another side of Antilochus. Achilles offered an enslaved woman skilled in handiwork and a tripod to the winner, a mare for second place, a cauldron for third, gold for fourth and a two-handled vessel for fifth. Eumelus, Diomedes, Menelaus, Meriones and Antilochus entered. Nestor warned his son that his horses were slower than those of his rivals and that careful driving would have to make up the difference. During the race, Apollo knocked away Diomedes' whip, but Athena restored it and then broke the yoke of Eumelus's chariot. Eumelus fell behind, and Diomedes drove on to victory. Antilochus's contest with Menelaus depended less on divine assistance than on his willingness to force an opening where another driver could scarcely follow.

At a narrow, rain-damaged part of the course, Antilochus pressed ahead despite Menelaus's warning that there was not room to pass safely. Menelaus checked his team rather than risk a collision, and Antilochus secured second place. Afterwards the Spartan king challenged him to swear that he had not deliberately obstructed him. Antilochus declined the oath, admitted the rashness of youth and handed over the prize mare. Menelaus accepted his explanation and returned the animal, restoring their friendship. A later event at the same games produced a separate reward. Antilochus finished third in the footrace, behind Odysseus and Ajax son of Oileus, and made a playful speech about the gods favouring older runners while praising Achilles. Achilles gave him another half-talent of gold, doubling that race's prize. The extra gold belongs to the footrace, not to the settlement of the chariot dispute.

Antilochus's death belongs to stories set after the Iliad. Memnon, the son of Eos and Tithonus and king of Aethiopia, arrived to aid the Trojans. The surviving summary of the lost Aethiopis records that Memnon killed Antilochus and that Achilles killed Memnon in turn, but it does not preserve a warning oracle addressed to Antilochus. Pindar gives the death its filial meaning: an arrow from Paris had wounded one of Nestor's horses and stopped his chariot, leaving him exposed to Memnon. Antilochus answered his father's cry and stood against the attacker, buying Nestor's escape with his own life. Quintus of Smyrna tells a fuller battle narrative in which Antilochus, while opposing Memnon, kills an Aethiopian companion identified as a son of Pyrrhasus. The passage does not give that companion the name Aesop.

The loss brought Achilles into conflict with Memnon. In Quintus's account, Nestor appealed to Achilles after his son's death, and the two great warriors met in armour made by Hephaestus. Their divine mothers and the gods formed part of the larger epic drama, but there is no need to combine every later embellishment into one fixed account. Achilles killed Memnon; the summary of the Aethiopis then tells how he drove the Trojans back towards the city and was himself killed by Paris and Apollo. It does not specify a wound in the heel. The succession of deaths makes Antilochus part of the same tragic pattern as Patroclus: the death of a companion is answered by vengeance, and the avenger's own life is drawn towards its end. Nestor survives the son who had protected him.

The Odyssey preserves a precise distinction in the burial tradition. Achilles' remains were mingled with those of Patroclus, while those of Antilochus lay separately, associated with the same great memorial on a headland beside the Hellespont. His ashes should therefore not be described as mixed with theirs. The poem also places his shade with Achilles, Patroclus and Ajax among the dead. Other accounts developed different heroic afterlives, but Homer's meeting is not presented as a scene in the Elysian Fields. Pindar remembers Antilochus above all as an example of honouring a parent through action. The memorial traditions and the poetry preserve complementary images: the friend beside other friends, and the son whose decision allowed his father to escape.