Kingdom Hearts
In Kingdom Hearts, Iago was Jafar's servant. He played a minor role, normally just appearing on Jafar's shoulder in cinematics, though he was the one who stole Genie's lamp from Aladdin. He later appeared holding Jafar's lamp in the boss battle, and flew around with it. The lamp was one of the ways to damage Jafar. Like the movie, Iago tried to fly away at the downfall of Jafar, but ended up in the lamp as well.
 Kingdom Hearts: Chain of Memories
Iago made a small cameo appearance in Kingdom Hearts: Chain of Memories, holding the lamp during the Jafar boss battle, like in the first game. He was also how Jafar got his hands on the lamp in this game to control Genie.
 Kingdom Hearts II
In Kingdom Hearts II, Iago, like The Return of Jafar, was finally free from Jafar's lamp. When he encountered Sora and the others again, he tried to convince them that he had turned over a new leaf, although only Goofy seemed to believe him until Iago saved the group from a bunch of Heartless.
Iago wanted to prove to Aladdin that he was no longer a villain. He did so by taking Jafar's lamp from Pete, which proved his loyalty, until Jafar was released and he was forced to trick Sora, Donald, Goofy, and Aladdin into going to the ruins, thereby destroying any trust he had obtained. When the group returned to Agrabah to face Jafar, Iago blocked an attack aimed at Aladdin and proved himself a friend again.
 Kingdom Hearts coded
Iago appears in Kingdom Hearts coded and helps Jafar like he did in Kingdom Hearts. Iago steals the Genie's lamp which Sora must get back. He also appears in the final boss fight, once again holding Jafar's lamp.
Iago is a cowardly parrot, who is often frustrated and vocalizes his anger freely. Iago is scared quite easily, especially by the person he fears the most—Jafar. Iago is very loyal to Jafar, mainly due to the immense fear of punishment he would receive should he fail his master. Although Iago gives off a "tough guy" exterior, he has a good heart, as seen in the second return to Agrabah in Kingdom Hearts II, when Iago shields Aladdin from one of Jafar's attacks, nearly sacrificing himself.
Though it is not mentioned in the movie or games what species of parrot Iago is, he strongly resembles a plump scarlet macaw. Most of his plumage is red, except for his tail and the tips of the first four feathers on each wing (Iago uses these feathers as "fingers"). Iago's sclera are yellow and his eyes are surrounded by a white, featherless area. He also has a large, yellow-orange beak and orange talons. His similarities to real-world birds end there, however. Iago's talons have three toes arranged in such a way that he has two in the front and one in the back, as opposed to real macaws having four toes, two in the front and two in the back. He has a thick black "uni-brow" and three thin, black feathers sprouting out of the top of his head. Iago's eyes are also set facing forward, unlike any species of macaw (and most species of birds). Arguably the biggest difference between Iago and other birds is the fact that he has straight, white teeth in his beak like a human, and his tongue is rather human-like as well.
Iago originally appeared in the 1992 film Aladdin. In the movie, he was Jafar's parrot and helped Jafar with his plan to marry Jasmine and become sultan of Agrabah. Iago is the one who steals the magic lamp from Aladdin and gives it to Jafar. In the climactic battle, Iago briefly fights Abu until Abu knocks him out for a few moments. Once Jafar is tricked into wishing to be a Genie, he is sucked into his new lamp. Iago tries to flee, but is grabbed by Jafar and trapped inside the lamp along with his master.
In The Return of Jafar, Iago had escaped from the lamp, he switches sides, mostly because he is fed up with being pushed around by Jafar. Over the course of the film, Iago slowly warms to the idea of friendship after Aladdin saves him from the Sultan's wrath in return for Iago unintentionally saving him from Abis Mal, finally risking his life to kill Jafar by pushing his lamp into molten lava. After his heroic deed, he is welcomed into Aladdin's extended family.