Just like his father, Max is dyslexic and has to work extra hard to succeed in school though he has tried to get out of school on a number of occasions. He is an avid skateboarder.
Because he was having problems sleeping and focusing in school, Vic suggested that Max take boxing lessons, but his parents made him quit when they realized the true danger surrounding the sport. He has a crush on Veronica and from time to time hits on her, despite them being cousins (to which Veronica either is creeped out or laughs it off). He can usually be found trying to spy on her and then denying it. He has also been seen looking through a peephole when one of Carmen's friends got undressed.
After getting some "player" teachings from George, Max had a girlfriend named Cristy Chapman. When his parents asked him if he had any sexual contact with her, he replied "I've only had upstairs outsidies", meaning he felt her breasts from the outside of her shirt. When he contracted urinary tract infection, he unintentionally started wetting the bed. Both Angie and her father suspected that Max got it from sexual activity with Cristy, but it wasn't from that. He had surgery that corrected it.
Also, later in the series, George, occasionally but vaguely, mocks Max because of his dyslexia even though he, himself, also has dyslexia. Max also had a period of time where he wet the bed,because of a bladder infection that he had for several months until his dad found out. George had this problem as well and his mother made sure her friends found out when he was young.
Max is attractive and received braces later in the series. He thought he looked like a dork with them on, so he attempted to get them loosened so he might be able to take them off.
Jokes are often made about Max's long shaggy skater hair, e.g. George often says he needs a haircut or someone thinking Max looks like a girl. In the last season his hair is cut much shorter and he has a much deeper voice. Max is also usually seen with a skateboard and in skater clothes. During the last season, he is shown to have developed into a rebellious skater teen with a more mature voice.
Max's personality changes slowly as the series goes on. For example, at the beginning of George Lopez, Max appears to be a curious, sweet, young boy who has severe problems with grades in school. However, during a certain point in the series, Max started hanging out with some toxic kids. For a short amount of time, became a careless, rebellious, smart-mouthed, back-talking, jerky type character. He does move out of this phase rather quickly and slowly grows into a more well-meaning and kind young man, even though he does still get into trouble on occasions.
At the end of the series, Max's trouble with numbers and dyslexia is emphasized. Despite this, he is more cooperative and much less troublesome than Carmen was when she lived at the Lopez home. Max displays a clear progression as a person throughout the show, and the maturity he shows in later seasons reflects his greater understanding of responsibility.