Max von Sydow did not receive an Oscar nomination, despite being nominated for a Golden Globe, for portraying Father Lankester Merrin in The Exorcist.
Max von Sydow does not appear again until late in the film when Merrin is called in to exorcize the demon that has possessed Regan MacNeil (Linda Blair). Sydow despite only showing up for a few scenes near the end of the film makes a considerable impact. What works well about his performance is the dynamic between his portrayal of Mirren and Jason Miller's portrayal of Father Karras. Where Miller portrays Karras as a hesitate priest filled with doubts, as well as being quite lost when it comes to dealing with the possession, Sydow portrays Merrin as man with a full grasp and command of the situation. When he first comes in telling Karras about the Demon Sydow makes Merrin a man with a clear understanding of the situation.
In the actual exorcism scenes Merrin goes directly at the demon. In the scenes Sydow is a constant of strength as he shows no hesitations as he fiercely goes against the demon. Sydow's performance is very effective portraying a passionate force for good against the demon. He brings the appropriate power to the situation from the front of the priests and stands as a man of conviction within the chaos of the demon. Within all the insanity of these scenes it would have been easy frankly to get lost within the craziness that is going around them and be completely forgotten in face of the possessed girl. He and Miller both stay in the scene and their realistic reactions add greatly to the film.
Sydow in his few scenes makes Mirren exactly what he should be which is almost a comforting factor in the film, to show someone who seems to be able to stand up against the evil of the demon. Sydow is moving in the way he is quietly reassuring in his scenes, particularly when he attempts to explain why the demon uses the girl to Karras. Sydow acts as the steadfast faith in the pivotal moments against Miller's doubting Karras. When Sydow leaves the film suddenly it has the proper disconcerting affect it should because of Max von Sydow's proper portrayal beforehand. In the title role he delivers the precise spiritual reinforcement required of him through his quiet but forceful performance.