Even Evil Has Standards: Yeah, he's a bully, but he being an "alpha-bully" he declared the disabled Stevie "off-limits" for bullies (inlcluding him). In fact, making sure the other bullies respected his standards eventually became his reason to retain his alpha-bully status.
Even when he finally snaps and decides to beat up Stevie, Reese completely numbs and weakens his own legs to make it a "fair fight."
Also, while he makes other nerds do his homework for him, he doesn't want to interfere with their weekends.
A good example? After Malcolm give him a book report guaranteed to be an A, his (then) girlfriend, Alison, realizes that she forgot to do hers, lamenting on how she can't afford another F. Reese's solution? Tearing the report in half, insuring that "now [they'll] both get Cs".
Calling The Parents Out: He frequently manages to get revenge against Hal and Lois whenever they neglect him or treat him unfairly. Hal forgot his birthday led to Dewey publicly shaming him in front of every single attendee at a Bridal expo. Lois saying she couldn't get a vital component to a science experiment (which led to Dewey failing) resulted in Dewey Gaslighting her. And for the most part, he actually gets away with it.
Character Development: Undergoes this more than any other character (with the possible exception of Francis). Over the course of the series, he evolves from a ditzy Cloudcuckoolander with an overactive imagination into a Wise Beyond His Years child prodigy who is just as smart as (if not moreso than) Malcolm. Justified, given that he ages through the most critical period of child development during the time course of the series (going from a pre-adolescent child in the pilot to a young teenager in the finale).
Ignored Epiphany: Tried to explain one to Reese and Malcolm in Buseys Run Away. After finally being put in a normal classroom, Dewey lacks the drive to commit heinous pranks with his brothers like he used to. Therefore, he starts bonding with Lois while Malcolm and Reese keep getting punished. They don't understand what's going on, and Dewey tries to explain that the reason Lois is acting so nice to him, is that he hasn't done anything stupid or destructive, so she hasn't needed to punish him. "It's not her, it's us." His brothers didn't get what he was saying and automatically assumed he's become Lois' spy.
Calling The Old Lady Out: Frequently rebels and insults Lois, and it is heavily implied that it is for no other reason than just to spite her.
His female equivalent, Frances, is similar, although her hate is more directed towards her dad, blaming him for none of her marriages working out.
Character Development: He becomes a lot more responsible as the series progress. In fact, many later episodes deal with how he fights his insane impulses (like when he warned Reese against collecting toilet rings from a dump like he did as a teen but ended up trying to beat Reese's record.) By the end, he is married and in a stable office job that, unlike Hal, he likes.
Cool Big Bro: He's seen this way by Malcolm, Reese and Dewey.
Enfant Terrible: In the episode Lois fights Jamie, in flashback form, we learn that Francis was absolutely horrible as a toddler. Probably the worst act he committed was using the last of the china to pour a flammable substance (lighter fluid) onto his teddy bear, and then set it on fire, which also resulted in Lois becoming the mother she currently is. It's also hinted that Lois's attempt at loving Francis (by placing the already burning teddy bear in the fireplace, burning her hand in the process) was a painful memory for him, given his reaction when he tells Lois this.
Even Evil Has Standards: He refused to fight against his boss, Lavernia, because she is a woman — until she ended up mocking his mother. He then fights back and the fight ended with a draw.
Fourth Date Marriage: He and Piama knew each other a very short time before getting married. Slightly deconstructed when there are several moments where they wonder whether their relationship can work out, but ultimately they remain together.
Never My Fault: He tries to pin (almost) all of his faults on his mother. In fact, he was legitimately stumped when his C.O. told him to think of one thing that he did wrong that he doesn't blame on his mother. The only time he actually did admit to wrongdoing without blaming his mother or anyone else was when he admitted that it was his fault that his brothers turned out the way they did.
Playing with Fire: This is what causes Lois to attempt to pull a complete 180 on her raising methods (he nearly set his teddy bear on fire, and the fact that he was pouring gasoline on it and then attempting to light it implied that he was doing so deliberately)
Troubling Unchildlike Behaviour: As a toddler, Francis attempted to douse his teddy bear with gasoline and then set it on fire before Lois intervened. Later, as a child, he had locked his parents out of the car while his mom was going into labor, and he also frequently tortured his brothers, stole their toys, locked them in a closet, and at one point scarred Reese with a bayonet.
Abusive Parents: Aside from the well known Financial Abuse, she is also implied to be physically abusive, given what Francis commented on what things his brothers should resist in regards to possible methods of extracting who burned her dress, and his resistance to a hazing from a cult on the military school resulted in their adopting Lois's methods. Of course, then again, given his obvious hatred for his mother, it's possible that he either lied about it or led himself to believe it.
She originally intended to subvert it, as she intended to make her household lax of rules specifically because she didn't want to have her children go through the life she herself had to put up with Ida. Unfortunately, Francis as a child proved how faulty that line of thought was when he did several bad things which came to a halt when he attempted to douse his teddy bear with gasoline and set it on fire.
In addition, she herself was a victim of parental abuse via her mother. It is implied to be far, far worse than anything she puts her own kids through, and unlike Lois (who as described bellow acts this way in order to keep her boys safe), doesn't do it to protect Lois, she's just a horrible, spiteful old woman.
Following the incident with the teddy bear mentioned above, Lois had calmly and firmly describe to baby Francis that from that point on she would do everything in her power to keep him and any other child she might have as safe as possible, regardless as to whether or not her kids would hate her for it. Lois knows very well how her kids feel about her parenting, but she legitimately does not care because she's willing to live with them hating her as long as they're safe and alive.
Ax-Crazy: Not to Francis's or Reese's level, but she does have her moments.
Hypocrite: In the episode she gets Malcom a job at her store, in a variety of different way. Malcolm calls her out on it repeatedly given how strict and principled she is at home, but she is utterly remorseless about it, spinning it as him learning harsh lessons about life.
One-Hour Work Week: Mostly averted though he is later revealed to have not worked on a friday in fifteen years. Possibly justified by how corrupt the company is and unimportant Hal's contribution is.
Papa Wolf: In the episode dealing with an alternate timeline where Lois had daughters instead of sons, Hal, although overweight, is also extremely protective of his daughters, although his daughters aren't appreciative of his efforts.
What, Exactly, Is His Job??: His exact job is somewhat vague though it is known that he works for a large corrupt company and works out of a cubicle. He views it as unimportant and notes he could be replaced easily.
Played by: Craig Lamar Traylor
The Tropes that are associated with this character are:
Corrupt the Cutie / Took a Level in Jerkass: Starts off the series as a rather innocent kid (thanks to over protective parents), but then he started hanging out with Malcolm and his family. Downplayed somewhat, however—from his first appearance he's willing to use his disabled status for a Wounded Gazelle Gambit
Handicapped Badass: He started out as quite innocent and helpless but as the series progresses he becomes much more confident. He joined the schools wheelchair basketball team, uses his wheelchair as a weapon against bullies (by running them over) and was revealed as the badass street racer in one episode. Interestingly, a lot of this takes place after his Mom leaves, suggesting it was her over-protectivness that made him under confident.
Oblivious to Love: Lois was oblivious to his obvious crush on her during the first few seasons. When he finally confesses his love for her when the store is being robbed, she delivers a "You're Not My Type" speech to him, and they remain friends.
Pet the Dog: She had some sociopathic examples of esteem and self-sacrifice which help explain why Lois still cares more than she should about her.
Racist Grandma: To the point where Lois and Francis make a plan with their (African-American) friends to get Ida out of their house so Lois could not have her there when she gives birth. It works too, until her waters break.
This trope seems to be subverted when Ida reveals she's engaged to a man from Hong Kong, but it turns out she just wanted his money.
Benevolent Boss: Otto is extremely accommodating to his workers. Francis once refers to him as "the best boss he's ever had."
Europeans Are Kinky: Francis rewrites a scene from a porno he mistakenly allowed to be filmed at The Grotto to keep it clean for their sake, only to find out they were disappointed that the scene contained no sex.