At the start of the story, Jess is someone of whom others take advantage. His sisters are selfish teenagers who regularly shirk their duties and leave Jess "to do the work as usual" (Ch.1). He likes to draw, but hides his creations, and he loves his teacher Miss Edmunds, but won't defend her when students talk badly about her. When Jess meets Leslie and shares the imaginary land of Terabithia with her, he discovers a true friend, one who believes in him and likes him for who he is. Jess tells Leslie of his frustration at not being able to draw like he wants to, saying, "I just can't get the poetry of the trees", and she responds quietly, "you will someday". When Jess is with Leslie, "everything seem(s) possible", his confidence grows, and he becomes increasingly more determined and assertive (Ch.4).
Jess is stronger when he is with Leslie, but he depends on her, needing her "to make the magic" (Ch.7). He is disgusted by his own fears, "as though he had been made with a great piece missing" (Ch.9), and he is furious when Leslie dies, because "she had made him leave his old self behind and...left him stranded" (Ch.12). It is not until she dies, however, that he discovers that his strength lies within himself. Jess is then able to help May Belle cross the bridge to Terabithia, and assume the role of mentor and leader, building her up as Leslie did with him.