Reese was a habitually mean child even in the womb, while Lois was in labor, he kicked her so hard that she delivered him prematurely. Immediately following his delivery he kicked the doctor in the nose. His obsession with violence horrifies the family and leaves him with few friends, partly as he is a bully at school. He bullies the "Krelboynes" in Malcolm's class, (except Stevie who, because of being paraplegic, is "off limits" except in certain situations), as well as his younger brothers, especially Dewey. Reese is often seen exercising, to build his muscles.
Reese generates a lot of dislike from people because of his psycho personality and his own family in general. He has very little (if any) empathy, and enjoys doing wrong just for the fun of it. He is shown to be quite cowardly when things go against him, and is quick to sell out members of his own family to save his skin.