He was portrayed by Michael Massee.
Ira Gaines and his gang of mercenaries were hired by Andre Drazen to assassinate David Palmer and frame Jack Bauer for it. Gaines hired Mandy to get Martin Belkin's ID card for him so he could disguise his sniper, Jonathan Matijevich, as Martin so he could shoot Palmer. Mandy's partner, Bridgit, tried to extort an extra million from Gaines by withholding the ID, but Gaines had Jonathan shoot her just as the deal was taking place.
Gaines also hired Dan Mounts and his friend Rick to kidnap Jack's daughter Kim. They kidnapped Janet York as well, but she was hit by a car and taken to the hospital. Dan told Gaines that Janet was dead, but when Gaines discovered that she was still alive, he killed Dan. It was not long after that Rick turned on him, although Gaines didn't know for a while.
Another of Gaines's men, Kevin Carroll, impersonated Janet's father Alan and killed her, although he was later found out. Despite this Kevin was able to help deliver Jack's wife Teri Bauer to him.
Gaines forced Jack to put a bug in his ear and told him to do everything he said, or he would kill Kim and Teri. He told him to kill Nina Myers (apparently unaware that she was also working for the Drazens), although Jack put a flak jacket on her so she survived. He told him to watch Jonathan kill David Palmer and accept the gun from him when the assassination was done, so it would look like Jack killed him. However, Jack instead shot at Palmer, intentionally missing him so that he would be protected from further assassination attempts.
Eventually, Kevin led Jack to Gaines's hideout, leading to a confrontation with Gaines and his men. In the resulting shootout, Gaines was severely wounded with a gunshot to the wrist. He told Jack that the people he worked for will kill him for failing his mission, and that no one could protect him, despite Jack saying he could. He turned around to shoot Jack, and Jack shot him in the chest, killing him.