Ed Harris portrays Christof who is the mastermind behind the Truman Show, holding over it with absolute sway. Harris besides a brief moment at the beginning of the film does not appear again into well into the film. Harris' performance here is all in his character creation of Christof. Christof certainly does not change throughout the film, and stays consistent in his role of controller. He is almost one note really until the very end of the film where he senses a loss of his power.
Harris's portrayal is interesting in the way he portrays Christof. He portrays him outwardly as some sort of sensitive artist very devoted to his passion project, the only problem is he seems to suffer from delusions of grandeur which is an interesting dynamic Harris creates within his performance. Harris always shows an incredible devotion in Christof to his show, and his position as the god of his world that he has created. Harris stays as a stoic figure, almost as if Christof is trying to be otherworldly even in the eyes of his colleagues.
Harris stays this way as Christof until the ending of the film when Truman attempts to escape the show. Harris is good actually as he shows Christof still attempting to be stoic, but with a great deal of urgency to get things back to order in his world. Harris carefully shows that Christof's derangement will actualyl bring him to kill his own creation, merely because it is not being controlled by him. Harris still keeps Christoff as a controlling individual, but there is a viciousness now behind his methods of control.
Harris's best scene though is his last one when Christof tries personally to convince Truman to stay in his world. Harris is very effective in this scene, still trying to play god, but this time with an attempt of almost fatherly warmth. It is a well handled scene, and in this moment Harris shows just how much this world, and Truman do mean to Christof, as it shows him shed the otherworldly quality he earlier always tried to convey. I must say I do like this performance, although I must say I do not find it amazing by any means, it is a fine performance from Harris.