Jack is a dedicated skateboarder who learned martial arts from his grandfather, Bobby Wasabi's former teacher. As a kid, he moved around a lot and is accustomed to being the outsider. Jerry, Eddie, and Milton invited him to sit with them in school even before he takes out four Black Dragons. Always trying to do the right thing, he will always be loyal to the guys for their initial acceptance. He follows theWasabi Code but one time broke it. But his was forgived by the gang.
Jack often has to inspire people to do their best. He is convinced Kim has a crush on him despite all the times Kim says she doesn't have a crush on him and might have a crush on her in return, since he is always staring and always trying to protect her from boys who try to break her heart. He was first seen in the dojo when he jumped through the wall to try to not be caught by the mall cops. He has a fear of clowns ever since he can remember. He can not stand the scent/taste of blue cheese. He is extremely loyal to his friends. For example, he saved the dojo from getting destroyed with a wrecking ball in dojo day afternoon. Lives by the Wasabi code ("We swear by the light of the dragons eye to be honest and loyal and never say die. WASABI"). In the episodeWax on, Wax off, it is shown he's the best at sparring. (badge on his costume which says ( "best sparring"). During My Left Foot, it is seen that Jack is not very good at football, barely even able to throw the ball. The episode also mentions he has a pet turtle. During Eddie Cries Uncle , it is revealed Jack is part of an intramural basketball team.