Perhaps what makes Montag a peculiar hero in Bradbury's Fahrenheit 451 is that he begins the novel as a villain of sorts. He is a fireman responsible for burning homes that hold books—items that are forbidden by the government. He sees nothing wrong with it, enjoying the process of burning:
It was a pleasure to burn.
It was a special pleasure to see things eaten, to see things blackened and changed.
However, when he responds to a call to burn a house and finds the owner still there, and further witnesses her willingness to die for her books by starting the fire that takes her life, he is a changed. It becomes a personal issue for him, and he can no longer continue as he had before.
Montag begins to think about the ideas that Clarisse McClellan presents to him. She advises him to slow down, pay attention—to think and live more fully. He starts to read and hide books. He gets in touch with Faber, a retired English professor, who knows the value of saving books and the knowledge that they hold. This is a dangerous proposition, but Montag is driven to change. He is unhappy in life, his marriage is a sham, and he discovers he can no longer burn houses.
A man who once burned homes and books, destroying lives and the intellectual process, decides he must take hold of his life and act differently. He first tries to save a woman who decides to burn along with her books.
"You can stop counting," she said. She opened the fingers of one hand slightly and in the palm of the hand was a single slender object.
An ordinary kitchen match.
She ignites the match and dies. Later, Beatty—Montag's boss—threatens to hunt down Faber:
"...We'll trace this and drop in on your friend."
"No!" said Montag.
He switched the safety catch on the flamethrower. Beatty glanced instantly at Montag's fingers and his eyes widened the faintest bit.
Montag kills Beatty, and in doing so, forever turns his back on the society in which he lives.
At the end, running for his life, he joins other people dedicated to creating a new way of life: protecting books and what they contain, dedicated to rebuilding society with hope for a liberated existence—allowed to think and learn without fear of punishment.
Montag began walking and...found that the others had fallen in behind him, going north. He was surprised, and moved aside to let Granger pass, but Granger...nodded him on. Montag went ahead.
Montag starts out destroying the lives of others. Interestingly, his actions are condoned by society. When he decides there is something inherently wrong with the government's complete control of society, he chooses to turn his back on social norms and becomes a hero—even though he is a non-traditional, "peculiar," hero.