What is so great about Lawrence of Arabia is its entire scope and that it never only settles on the central character study of Lawrence (Peter O'Toole), but it always manages to give an appropriate amount of time to the various supporting players who are well realized by the large cast. Although the film is filled with such actors well liked by the academy as Anthony Quinn, Claude Rains, Alec Guinness, Arthur Kennedy, and Jose Ferrer the only one of the supporting players nominated was Omar Sharif whose first English language film was this film. This certainly makes sense as Sherif Ali has an interesting transformation that is the opposite of Lawrence's central one of the film. Although it is not given an enormous amount of time through the film's strong script, and especially Sharif's performance it is fully realized. In his first scene Omar Sharif appears as Sherif Ali mercilessly kills a fellow Arab, Lawrence's guide, simply because the man was from the wrong tribe and drinking from his well.
Sharif is interesting in Ali first scene and shows absolutely no remorse over his killing. This important because Sharif shows with his lack of empathy that Ali's behavior is simply commonplace, he really sees no reason for an alternative. Also in this first scene Ali acts with certain interest as well as a very much unimpressed quality toward Lawrence. Sharif again establishes well Ali's whole past suggesting an intelligent man as well as one who is very skeptical of both the British's help and their longtime goals.
In their move to take Aqaba Sharif makes Ali act as an interesting contrast to Lawrence. Sharif shows that Ali is very much doubtful of Lawrence's plan, and his whole overly optimistic and passionate attitude. Sharif always plays down all of these scenes. He never acts as if this is some wonderful plan instead Sharif shows Ali overall cynicism involving the plan and Lawrence as well. He also stays consistently realistic in showing how although doubtful of the plan Ali still wants the plan to work therefore acts as a teacher to Lawrence showing his knowledge of the land.
In the whole of the Aqaba sequence Sharif undergoes a transition of both accepting of the idea, as well as excepting Lawrence as a man who honestly wants to help them. It is a subtle and effectively portrayed transition by Sharif where he never overplays it. He instead shows actually a slow removal of a sort of defense against outsiders he had from before, and Sharif naturally shows that Ali begins to accept Lawrence as one of their own. Sharif never pushes this change instead carefully showing it, which is essential since his defense against Lawrence briefly returns when Lawrence must leave to report on their success, it returns not in an overriding fashion but rather as Sharif showing Ali realistically was not completely sure of Lawrence just yet.
Later in the film it is interesting because Sharif shows that Ali no longer is a cynical almost adversary to Lawrence but his greatest confidant. It is interesting because Ali concerns change over from Lawrence's ability to Lawrence's mental state since Lawrence becomes increasingly involved with his own idea that he is some sort of savior. Sharif does not play it as finding Lawrence insane and treating him as such, but instead Sharif shows that from his time with Lawrence he does have an honest care for the man. Sharif is terrific in playing opposite of O'Toole being able to stay with O'Toole incredible performance as well as showing how Ali attempts to act as both a friend and reality to Lawrence.
The most interesting aspect of Sharif's performance though comes near the end of the film where Lawrence as become overwhelmed with sadism and revenge against the Turks. Sharif shows a very much changed man from the man who had originally killed without caring from the film, which is the opposite transition of Lawrence's. Sharif conveys this change superbly owing to his own horror at Lawrence's blood lust as well as his increased understanding of the fault of tribal politics. Sharif effectively portrays this change making Ali the moral center of the film at the end. He is particularly great in the massacre scene where Ali cannot even believe the degree of Lawrence's change and hatred. Sharif though ends on a high note as he shows Ali honest struggle, and heartbreaking realization in seeing the change in his friend. This is a great performance by Omar Sharif that effectively realizes Sherif Ali as a character, as well manages to keep his presence known despite the overwhelming strength of the lead performance.