Answer :

Montag transforms from blind civil servant - the "fireman" who operates blindly to the directions of society to as individual who's every action is an act of civil disobedience.  The act of possessing a book, taking a book from a fire, talking to the professor, reading the books and fleeing the city made him a criminal.  The reader sees these acts as heroic because he is finding his "humanity".     It is the act of disobedience and turning away from the societal norms -- finding something valuable in the pages of something forbidden that makes him a hero.Montag does not see himself as heroic but in memorizing the book of Ecclesiastes so as to save a piece of the past for future generations is  brave and heroic act.