Daniels anyway is brilliant in this performance in just the way he creates this character. This is a performance that can be taken as almost one note in the broad strokes, though that is not true due to the subtleties of Daniels's work. What Daniels does here is take self absorption to an all new level with his performance here as a once great writer who still considered himself so, even though no one else seems to. Daniels always is reassuring the fact that Bernard is as much into himself as a man possibly can. Daniels doesn't show a hint of doubt as he says such things as the Tale of Two Cities being "lesser Dickens" or than Kafka was one of his predecessors.
Daniels makes it clear throughout the film that he has no concerns in any way if people even doubt his genius because he is so self assured. Daniels is terrific here because there is not ever a doubt in our minds that he has no doubt about himself. Daniels is actually quite hilarious in how pure the self absorption is in his performance. Daniels portrays Bernard as a man very much in love with himself without the need for anyone else's approval because they are not geniuses like him anyways. It is almost a derangement considering how sure of himself he really is, but Daniels of course shows it only ever to be a calm very very collected derangement that Bernard has.
It is a brilliant note that Daniels plays the part at and really it would be wrong for Daniels to ever get off that note as Bernard never does lose his intense devotion to himself, even at the end of the film Daniels still stays firm in support of Bernard's derangement. Daniels shows that Bernard simply is incapable of losing his superiority complex. Daniels is pure as whether it is trying to teach his kids a lesson, or fighting with his wife Bernard never stops with his own approach of quiet reserved smugness. The only time he really breaks this frame is when he is shown not to be the best, and Daniels is quite good that only when pushed into a corner that exposes an inferiority does he break out in anger.
Daniels is brilliant in his broader creation of course, but his best moments perhaps are in the silent expressions of his performance. He is particularly excellent in any scene where someone praises Bernard's wife's writing in his presence. Daniels always portrays a deep wound in his face in Bernard anytime that he hears that his wife may be a better writer than he. Daniels is equally strong in his moments of interacting with his kids particularly when he expresses love to them. Daniels is particularly interesting in these seems as when Bernard tries to talk warmly to them he does and he doesn't. Daniels finds just the right difficult tone needed as Bernard does love his kids, but never enough to love them more than he loves himself.
This is a terrific performance by Jeff Daniels where he succeeds in making an extremely unlikable character extremely enjoyable to watch. The challenge of this character really is a big one in that Bernard could easily just be obnoxious with his constant self promotion, or dull with his relaxed manner of doing so. Jeff Daniels though more than meets the challenge presented by the character with such an effortless assurance with his performance. He simply has a grasp on the part, which is essential for this character to work as he really cannot have even the slightest doubts to be believed. Daniels makes the character his own being the entertaining despicable "genius" Bernard Berkman should be.