Jess is the principal character of Bridge to Terabithia. The story is told through his eyes, though not in his voice, and thus we are given a deeper glimpse at his soul and motivations than those of anyone else in the book. Jess sees himself as a very ordinary boy, at least until Leslie comes along. He is unable to identify those characteristics that distinguish him from the rest because he is constantly in conflict with the various facets of his life. He has several distinct roles that those around him expect him to play. His family expects him to be the dutiful son and brother, and his own personality often seems to be less important to them than his ability to get the chores done. His father, in particular, expects him to be a "young man," to look at the world from an adult and distinctly masculine perspective. Jess's personal passions and skills, such as art, are to be discouraged if they do not help him fit into this role. The students at school likewise expect him to conform, to throw himself wholeheartedly into pursuits such as sports. Amid all this, the only thing Jess can grasp that fulfills his expected responsibilities from all these people and which fulfills him personally is running, and he seizes on this fanatically, determined to distinguish himself as the fastest runner in the fifth grade. This, he feels, will free him from what he feels to be his curse of ordinariness, and will make him into a person that both he and everyone else can accept.

However, when Leslie comes along, we are allowed to see the true Jess shining through the poorly constructed mask of conformity. His artistic talent is the main tangible thing that distinguishes him from the rest, and Leslie nurtures this through encouragement and a gift of an expensive paint set. However, the importance of this talent pales beside the personal qualities Jess is finally allowing himself to acknowledge. He has the sensitivity and kindness that would probably be at odds with the "tough guy" image everyone seems to want him to project. He coddles his younger sister and even convinces Leslie to help the school bully, who has caused him and everyone else in the school untold annoyance and fear, when he finds out that she's crying in the bathroom. He is possessed of a sharp intelligence which he is able to put to use for the first time when confronted with the intellectual stimulation that Leslie provides, through her books and her imagination. Through his friendship with Leslie, Jess truly manages to find himself. But he is not simply dependent on her for this newfound sense of self; when she dies, he eventually finds that he can carry on and continue in the path of personal growth she has helped him to find. Jess is a thoroughly admirable boy on his way to becoming a man, and the story of his growth is the kernel of Bridge to Terabithia.