Oskar Werner did not receive an Oscar nomination for portraying Guy Montag in Fahrenheit 451.
Another strange choice made in this film is the casting of Oskar Werner as Guy Montag. He definitely is not the first name that comes to my mind when I think of an average man of the 60's. Stuart Whitman, if was in The Mark type form, probably would have been the ideal man for the part of Guy Montag who at the beginning of the story is suppose to be just an average cog in the machine of society. He works as a fireman and does his job just as he should without any problems. Werner though is a very good actor and despite maybe not being the perfect choice in terms of casting he still commits himself particularly early on in the film as Guy pretty much just does what he is told, and doesn't seem to have any qualms about it.
Werner, as he apparently stated himself, plays Montag in almost a robotic manner early on. This actually fits perfectly for Montag's role in the film as he just is fitting in his place and nothing more. Werner plays him repressed in his emotions quite effectively because he is a man who not only seems to care nothing about the things that he is burning and the ideas they represent, but as well at home where he should be happy he still seems aloof just a man going through the motions. Werner importantly doesn't make him sad really just almost in a trance of indifference to all that is going on around him and being exactly the servant that the society wishes him to be.
The transition of Montag is still handled pretty well by Oskar Werner at least in the beginning as he starts to question just burning the books and starts to read them. Werner brings a quiet emotional resonance as he frankly just loosens on the robotics of the man and we see a fire instead building in Montag. Werner actually keeps it rather subtle which works well for Montag's character since after all Montag still must keep his revelation to himself. Werner builds the emotional pressure in Montag as well as the interest in the nature of books as well as his anger involving the treatment of the books, and his initial bursts of emotion at his wife and her friends as their behavior still fits to what society desires.
A problem though arises later in the film as the development of Montag almost seems to stop and unfortunately Francois Truffaut seems to take over for Oskar Werner in the development of Montag. One of the most pivotal scenes in which it is discovered that Montag has been hiding books and reading them and he is instructed by his chief to destroy his own home Werner is barely shown. This is particularly notable when Montag turns his flamethrower to one of his fellow fire men where it is hard to notice what Montag feels in the scene since Werner is not really allowed to even show his reactions. This continues pretty much to the end where Werner is given very little to do and it is a shame as Montag final transition to a man away from his old shell could have been truly powerful if Werner had been allowed to honestly portray this.
I should note that whenever Werner is allowed to show how Montag is feeling toward the end he is good and believable still. Werner portrayal though mostly is just glimpses of the man. These are fairly basic reactions to just what is going on around him. To be completely fair Werner is always believable in these reactions and never once does he fall short in terms of his actual performance. His character arc though is cut short due to Truffaut basically putting his performance to the side for the ending. Werner really could have made Guy Montag's story from drone to a free man something very special if he had been allowed to bring Montag fully to the end of the journey. Oskar Werner certainly showed the promise of this in the first 2/3rds of his performance, but Werner's work is cut short.