Will is the major character in Something Wicked This Way Comes, although there are two other leading roles. Will starts out as a thoughtful thirteen year old who is less prone to action than his friend Jim. But as the story unfolds Will is often forced to be more active. Sometimes he even precipitates action on his own. In one notable instance, when he cuts the Dust Witch's balloon, Will acts completely on his own will Jim is sleeping. Perhaps Will was not inherently less active but simply enjoyed thinking things through and preferred thought to action. But as far as the carnival is concerned, Will never hesitates. He stops Jim from going on the carousel when Mr. Cooger is on it, and he stops Jim from communicating with Mr. Cooger on his own. Once he decides upon a course of action, Will sticks to it no less than Jim or anyone else. After Mr. Halloway frees Will from the Witch's spell he helps his father in the Mirror Maze and runs to get to Jim before Jim gets to the carousel.
But Will is also a very sensitive boy. He understands Jim and his father far better than either of the other two understand him. Will is very empathic and he feels bad when Mr. Cooger dies even though he does not want him alive. Although he is very bright for his age, there is also a sweetness in Will. He is not eager to grow up because he loves life right now. He loves his parents and he feels bad that his father is sad all of the time. Will feels too much for other people to be cruel or hurtful, yet he is confident enough in his reasoning to stop Jim from doing something that Jim wants to do simply because he knows it will be bad for his friend in the long run. Will also has a great instinct for what the right thing to do is, and sometimes his immediate decisions are shockingly quick even to Jim.
Jim is quick to think and quicker to act. He does not pause to think things through like Will does but rather goes with his gut feeling every time. Jim's mother cares for him very much but borders on being overprotective, even though Jim is anything but afraid of the world. He values his freedom above all else, and he vows never to have anything that can hurt him. Jim, unlike Will, is not constantly empathic. Sometimes he shows grave concern for others but at other times he can be almost oblivious to the dangers that surround those he cares about while he pursues his own ends. Jim's incredible tunnel vision makes him a great friend for Will, but in the case of the carnival it nearly provides drastic results. Once Jim has his sights set upon something he will not let it go, and so even though both Will and Mr. Halloway explain several times that the carousel is nothing but a cheap trick, Jim still desires it. He understands what they say when they explain that using it will alienate you from your friends, family, and possibly even yourself, but Jim also does not let anyone close enough to him for that to be a problem. If you cannot be hurt, then there is no harm in riding the carousel, except for the possibility that you become Mr. Dark's partner for eternity.
But fortunately for Jim other people are looking out for his well-being, even if he is not. Will and Mr. Halloway save Jim's life in the end of the book and when he comes to Jim seems to have changed slightly. He seems to truly care about his friends and is able to reason out for himself why the carousel is bad. The entire book in a way is Jim's journey to become comfortable enough with himself to let someone else in. Early on in the book he is willing to sacrifice Will in order to get on the carousel, but by the end Jim seems to know who is on his side and who is not.
The only grown up protagonist in the book, Charles Halloway is Will's fifty-four year old father. In the beginning of the book he is kind, caring father but one who does not relate at all to his son because he believes that his age makes it impossible. Mr. Halloway believes himself to be old, and his belief makes him older than his years. Throughout the beginning of the book he is slow to act and wary of interfering too much with his son's life, something that he considers outside of his domain, as an old man, to step into. At the same time as all of this is occurring he feels an empathy for his son and his friend because he longs for the days of his youth when he ran free and happy. At a critical moment in the book he shows himself to be a man of action, surprising even himself. He protects the boys from Mr. Dark and the Witch with poise and daring. Charles Halloway realizes that things are changing, and that point is driven home when Mr. Dark comes that night, takes the boys, and crushes his left hand. He is left behind to be killed by the witch, but suddenly Mr. Halloway stops pretending to be an old man and starts acting like the youthful fifty-four year old that he feels himself to be. Finally comfortable with his life, he begins to take the initiative, driving off the Witch and then storming the carnival for the final showdown. It turns out that a fully confident and content Charles Halloway is more than a match for the forces of evil, and he manages to bring Will and Jim home safe and sound.