Odysseus is a prominent figure in the story about his journey home after the Trojan War, The Odyssey; however, he is merely a supporting character in the Iliad by Homer. When we do see him, he is generally described as being "godlike" or somehow connected to the gods because of his wisdom or bravery. 

In book three of the epic story, Odysseus is being compared to Menelaus, a man who is imposing and impressive physically. Both he and Odysseus visited Antenor on a mission to arrange for the return of Helen, and Antenor talks about that visit here as he and others watch the preparations for the great duel, below the tower. 

But when the other [Menelaos] drove to his feet, resourceful Odysseus,
he would just stand and stare down, eyes fixed on the ground beneath him,
nor would he gesture with the staff backward and forward, but hold it
clutched hard in front of him, like any man who knows nothing.
Yes, you would call him a sullen man, and a fool likewise.
But when he let the great voice go from his chest, and the words came
drifting down like the winter snows, then no other mortal
man beside could stand up against Odysseus.

In a culture that equally values wisdom and physical prowess, Odysseus can hold his own. While he does not appear to be particularly sagacious, as soon as he speaks it is evident--even to Antenor, the king's wise counselor--that Odysseus is a gifted and wise orator.

In book two of the story, Odysseus is again compared to the chief of all the gods, Zeus; and when Odysseus speaks, he imparts wisdom and good counsel that should be heeded by all. Agamemnon has had a dream and is confident the gods are now on the side of the Achaians against the Trojans; he decides to test his army and announces that they are free to go home if they wish. Their response is not what he expected: they cheer loudly and head back to their ships, eager to go home rather than finish fighting the war they came here to fight.

Odysseus is visited by Athena and reminded of the losses the army has already suffered; leaving now would make those deaths a waste rather than a sacrifice. Odysseus takes Agamemnon's scepter and does this:

[W]hen he came upon some common soldier shouting, he drove him back with the sceptre and rebuked him: "Sit, man, and hear the words of better men than you; you are weak and lack courage, worthless in war or counsel. All cannot play the king, and a host of leaders is no wise thing. Let us have but the one leader, the one true king, to whom Zeus, the son of Cronos of wily counsel, gave sceptre and command, to rule his people wisely."

So with his lordly ways he brought the ranks to heel, and they flocked back from their huts and ships to the Assembly, noisily, like a wave of the roaring sea when it thunders on the beach while the depths resound.

The same men who had been rushing back to their ships, giddy at the prospect of returning home, now become an overwhelming tide of humanity flowing back to the battlefield. 

The Iliad is not Odysseus's story; however, he is certainly an integral part of what happens in it. He is a valiant warrior, but he is most known for his skills as a wise orator as well as his wiliness (craftiness, slyness) in using words to make things happen. He is a thinker and he is a hero, and we see these attributes whenever we read about him. In this story, he solidifies his reputation as a strong leader, which is why we are willing to follow his journey. Here, however, he does not suffer the missteps he will in The Odyssey.