Agamemnon is the former king of Mycenae and the brother of Menelaus, and he was the commander of the Achaean forces at Troy. He is a key character in Homer’s The Iliad, but in The Odyssey he has been long dead by the time Telemachus sets off on his journey to find Odysseus. Agamemnon himself only appears in Book 11 as one of the spirits that Odysseus meets in the underworld. However, his tale is spoken about at length by many characters, including Zeus, Nestor, Menelaus, and Agamemnon himself.

When Agamemnon returned from commanding the Greeks during the Trojan War, it was to find that Aegisthus, a base coward who remained behind while the Greeks fought in Troy, had seduced and married his wife, Clytemnestra. Aegisthus and Clytemnestra then murdered Agamemnon, enabling Aegisthus to seize control of Agamemnon’s kingdom. The lovers were thwarted when Orestes, Agamemnon and Clytemnestra's son who was exiled in Athens, returned home and killed Aegisthus and Clytemnestra for betraying and killing his father. Agamemnon’s tale has a symbolic role in the narrative because its setup parallels the Odyssey’s exposition. Just as Aegisthus took advantage of Agamemnon’s absence to consort with his wife, so too, have Penelope’s suitors exploited Odysseus’s possible death in the Trojan War to gorge themselves on his provisions and pursue Penelope. Odysseus finds himself in the same position that cost his fellow commander his wife, his property, and his life, and narratively it spells out the stakes for the reader, illustrating what might happen should Odysseus fail to return soon. Furthermore, Orestes’ narrative parallels that of Telemachus, and Agamemnon’s bitterness towards his wife characterizes Clytemnestra as a foil to the ever-loyal Penelope.