SharkBoy is rather headstrong and aggressive compared to others in the group. Still, he has a caring side that he's reluctant to show, unless it's for LavaGirl, who he's shown to be protective over. He's occasionally impulsive and sometimes needs convincing to follow a line of logic if it doesn't sound foolproof or if it goes against what he wants to do.

He's quick to anger but that doesn't mean he's incapable of being intelligent. He seems to prefer lending a hand rather than a mind.