He was a Greek warrior and the King of Ithaca, the husband of Penelope and father of Telemachus.
Odysseus was best known for deceiving the King of Troy with the Trojan Horse trick which allowed the Greeks to enter the city of Troy and destroy it, thus decisively winning the Trojan War. After the victory, Odysseus was supposed to sacrifice a lamb to Zeus as gratitude for winning the war, but Odysseus refused as he considered it barbaric. He then announced he was going home to Ithaca and to Penelope. Zeus, however, was angry with Odysseus for refusing to make the sacrifice and refused to let him return directly home, instead sending him on a journey where it took him ten years to get back to Ithaca (in addition to the ten years fighting in the Trojan War). Along the way, Odysseus and his crew had a narrow escape from the Sirens. The crew were killed, however, when they were turned into pigs and eaten by Odysseus (who was unaware of their transformation) at Circe's island. Odysseus ended up having to sail the River Styx in order to get back to Ithaca.
When Odysseus finally got home, he killed the suitors who had taken up residence in his house and were seeking Penelope's hand in marriage. When Penelope asked him to spend some time with her, he complained that she was smothering him and went to Moe's instead.
He is voiced by Dan Castellaneta.