Below are quotations selected from a number of sources which address the character of Sir Gawain:
"In the earliest Arthurian stories, Sir Gawain was the greatest of the Knights of the Round Table. He was famed for his prowess at arms and, above all, for his courtesy. ... Here Gawain is the perfect knight; he is so recognized by the various characters in the story and, for all his modesty, implicitly in his view of himself. To the others his greatest qualities are his knightly courtesy and his success in battle. To Gawain these are important, but he seems to set an even higher value on his courage and integrity, the two central pillars of his manhood. The story is concerned with the conflict between his conception of himself and the reality. He is not quite so brave or so honorable as he thought he was, but he is still very brave, very honorable. He cannot quite see this, but the reader can.
The character of Sir Gawain is relatively fixed by tradition; he cannot act very differently from the way he does. In consequence, his character is static--is, indeed, less interesting than that of his adversary, the Green Knight. But it is for other qualities than character interest that Sir Gawain and The Green Knight is valued." (G. B. Pace, 35)
"We are placed on the side of mortality itself, and can thus, with the Green Knight, forgive Gawain for his single act of cowardice: what he did was done not out of sensual lust but for love of life--'the less, then, to blame.' In the context of this affectionate sympathy, Gawain's own violent anger at the revelation of his fault must itself be viewed with amusement, as part of his human fallibility." (Marie Borroff, Introduction)
"Gawain is, naturally, more fully drawn than any other character. Not only do we observe him ourselves, we are told how he impressed other people in the story and how he himself thought and felt. We see him behaving, as all expect him to do, with exquisite courtesy; but we also see what is not apparent to the other characters, that such behavior does not always come easily to him. All the time that he is parrying the lady's advances, we are aware that he feels himself to be on a knife-edge between discourtesy and compliance." (Dorothy Everett, 16)
"Indeed, a mystery surrounding the Green Knight is essential for the effect of the poem, which is to show Gawain being submitted to the unexpected--not to the test he expects, but to one he does not expect. He expects (and we expect with him when we first read the poem) that the real test he has to nerve himself for is meeting the Green Knight at the Green Chapel and receiving a presumably mortal blow from his axe. But when, after a tremendous effort of will, he does bring himself to face the Green Knight and accept the blow, it turns out that this is not the test itself; it is only the symbol of a previous test which was carried out by the Green Knight's wife, and which Gawain has already failed."
"When he resumes his quest for the Green Chapel and leaves the luxurious castle behind there is room once more for heroism in his behavior, and indeed he shows heroism of a particularly touching kind--not the kind that knows no fear, but the kind that overcomes a fear to which all the senses are sharpened. He proudly turns aside the suggestion of his guide that he should go back to Camelot, and nobody would know that he had not faced the Green Knight, saying that if he did that, even though nobody found out, he would still be a 'kny3t kowarde' (2131)." (A. C. Spearing, 102)