John Proctor is a man of high personal integrity who struggles with guilt. His extramarital affair with Abigail fills him with self-loathing because he expects honesty and integrity in others, but is disappointed in his own failure to remain faithful. He refuses to confess or to play the game that is taking place in the witch trials, until he realizes that holding tightly to his integrity will not have much impact if he is executed. He also realizes he cannot fulfill his commitment to his wife Elizabeth if he leaves her in this way.
Proctor has stood out among his peers in Salem Village as someone who rejects the status quo; he does not like the Reverend Parrish and considers him greedy and dishonest. He does not attend church regularly because he doesn't believe in hypocrisy, and his own guilt prevents him from wanting too engage int his hypocrisy. Proctor's disdain for his peers and his tendency to speak his mind are somewhat respected in the village, but his righteousness backfires when he is also accused, a fate he had believed would not befall someone as strong and intelligent as himself. Seeing through the games being played by the young accusers (his former paramour Abigail among them), he decides to publicly admit his infidelity in order to discredit the lies and save his wife's honor (Elizabeth was also accused).
Proctor ultimately decides that "confessing" in the way the judges want him to will allow him to have his life and that by knowingly admitting he is guilty he can go forward with the truth once the trials are over. But he is pushed past his breaking point, and when he is compelled to sign a document proclaiming his guilt, he refuses and is put to death.